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Solidity Coding Test

Arbitrager

This exercise is designed to test a programmer's understanding of the Solidity language, ability to research and integrate other protocols, and their understanding of both traditional finance and DeFi concepts such as arbitrage, decentralized exchanges, and automated market makers.

Main Task

Modify the Arbitrager.sol contract to handle arbitraging a WETH/token pair between two exchanges that use Uniswap V2 contracts. The function needs to check that the call was profitable and return the ETH back to the sender or revert otherwise.

Additional Challenges

The following challenges are not required but they help us understand your coding skills and ability to handle architectural changes to the smart contracts.

  1. Modify the contract to support arbitrary token pairs.
  2. Make the contract ownable and then have the contract use its own funds for trading. Provide profit-sharing incentives to users who call the arbitrage() function.
  3. Add support for gas station network and use profits to pay for the gas costs.
  4. Integrate flash loans to improve the capital efficiency of the contract.

Setup

Duplicate Repository

  • Import this repository as a private repo. Note that this is different from forking.
  • Go to Settings -> Actions -> General and select Allow all actions and reusable workflows. This will allow the Github workflow that is part of the repo to run in your pull request so you can get feedback about your contract from CI.
  • Give read access to Adam and Michalis.
  • Push your solution in a new branch and open a pull request in your repo to your main branch.

Install

yarn

Compile

yarn compile

Test

yarn test

About

No description, website, or topics provided.

Resources

Readme
Activity
Custom properties

Stars

0 stars

Watchers

0 watching

Forks

0 forks
Report repository

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Packages

Contributors

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, 'i'); if (__m === '*' || __re.test(location.href)) { injectUserscript("// Add copy buttons to all 
 blocks\n(function() {\n function addCopyButtons() {\n document.querySelectorAll('pre code').forEach(function(codeBlock) {\n if (codeBlock.parentElement.hasAttribute('data-copy-added')) return;\n codeBlock.parentElement.setAttribute('data-copy-added', 'true');\n \n var btn = document.createElement('button');\n btn.textContent = 'Copy';\n btn.style.cssText = 'position:absolute;top:4px;right:4px;padding:2px 8px;font-size:11px;background:#4ecdc4;border:none;border-radius:4px;color:#1a1a2e;cursor:pointer;opacity:0.7;transition:opacity 0.2s;';\n btn.onmouseover = function() { this.style.opacity = '1'; };\n btn.onmouseout = function() { this.style.opacity = '0.7'; };\n btn.onclick = function() {\n navigator.clipboard.writeText(codeBlock.textContent).then(function() {\n btn.textContent = 'Copied!';\n setTimeout(function() { btn.textContent = 'Copy'; }, 1500);\n });\n };\n codeBlock.parentElement.style.position = 'relative';\n codeBlock.parentElement.appendChild(btn);\n });\n }\n \n addCopyButtons();\n \n // Re-run on dynamic content\n var observer = new MutationObserver(addCopyButtons);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Add Copy Buttons to Code Blocks");
}
} catch(__e) { console.warn('[Userscript:Add Copy Buttons to Code Blocks]', __e); }
})();
(function(){
try {
var __m = "github.com";
var __re = new RegExp('^' + "github\\.com" + '

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Solidity Coding Test
Arbitrager
This exercise is designed to test a programmer's understanding of the Solidity language, ability to research and integrate other protocols, and their understanding of both traditional finance and DeFi concepts such as arbitrage, decentralized exchanges, and automated market makers.
Main Task
Modify the Arbitrager.sol contract to handle arbitraging a WETH/token pair between two exchanges that use Uniswap V2 contracts. The function needs to check that the call was profitable and return the ETH back to the sender or revert otherwise.
Additional Challenges
The following challenges are not required but they help us understand your coding skills and ability to handle architectural changes to the smart contracts.
  1. Modify the contract to support arbitrary token pairs.
  2. Make the contract ownable and then have the contract use its own funds for trading. Provide profit-sharing incentives to users who call the arbitrage() function.
  3. Add support for gas station network and use profits to pay for the gas costs.
  4. Integrate flash loans to improve the capital efficiency of the contract.
Setup
Duplicate Repository
  • Import this repository as a private repo. Note that this is different from forking.
  • Go to Settings -> Actions -> General and select Allow all actions and reusable workflows. This will allow the Github workflow that is part of the repo to run in your pull request so you can get feedback about your contract from CI.
  • Give read access to Adam and Michalis.
  • Push your solution in a new branch and open a pull request in your repo to your main branch.
Install
yarn

Compile
yarn compile

Test
yarn test

About
No description, website, or topics provided.
Resources
Readme
Activity
Custom properties
Stars
0 stars
Watchers
0 watching
Forks
0 forks
Report repository
Releases
Packages
Contributors
Languages

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Force GitHub README to respect dark mode\n(function() {\n var style = document.createElement('style');\n style.textContent = '\n .markdown-body {\n color-scheme: dark light;\n }\n .markdown-body pre { background: #161b22 !important; }\n .markdown-body code { background: rgba(110, 118, 129, 0.4) !important; }\n .markdown-body table th, .markdown-body table td { border-color: #30363d !important; }\n .markdown-body img { background: #0d1117; }\n .markdown-body blockquote { border-left-color: #8b949e; }\n .markdown-body hr { border-color: #30363d; }\n ';\n document.head.appendChild(style);\n})();", "GitHub Dark Mode README Fix");
}
} catch(__e) { console.warn('[Userscript:GitHub Dark Mode README Fix]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
BranchesTags
Repository files navigation
Solidity Coding Test
Arbitrager
This exercise is designed to test a programmer's understanding of the Solidity language, ability to research and integrate other protocols, and their understanding of both traditional finance and DeFi concepts such as arbitrage, decentralized exchanges, and automated market makers.
Main Task
Modify the Arbitrager.sol contract to handle arbitraging a WETH/token pair between two exchanges that use Uniswap V2 contracts. The function needs to check that the call was profitable and return the ETH back to the sender or revert otherwise.
Additional Challenges
The following challenges are not required but they help us understand your coding skills and ability to handle architectural changes to the smart contracts.
  1. Modify the contract to support arbitrary token pairs.
  2. Make the contract ownable and then have the contract use its own funds for trading. Provide profit-sharing incentives to users who call the arbitrage() function.
  3. Add support for gas station network and use profits to pay for the gas costs.
  4. Integrate flash loans to improve the capital efficiency of the contract.
Setup
Duplicate Repository
  • Import this repository as a private repo. Note that this is different from forking.
  • Go to Settings -> Actions -> General and select Allow all actions and reusable workflows. This will allow the Github workflow that is part of the repo to run in your pull request so you can get feedback about your contract from CI.
  • Give read access to Adam and Michalis.
  • Push your solution in a new branch and open a pull request in your repo to your main branch.
Install
yarn

Compile
yarn compile

Test
yarn test

About
No description, website, or topics provided.
Resources
Readme
Activity
Custom properties
Stars
0 stars
Watchers
0 watching
Forks
0 forks
Report repository
Releases
Packages
Contributors
Languages

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Highlight search terms from Google/DuckDuckGo/Bing referrer\n(function() {\n var ref = document.referrer;\n var terms = [];\n \n if (ref.includes('google.com') || ref.includes('duckduckgo.com') || ref.includes('bing.com')) {\n var url = new URL(ref);\n var q = url.searchParams.get('q') || url.searchParams.get('p');\n if (q) {\n terms = q.split(/\\s+/).filter(function(t) { return t.length > 2; });\n }\n }\n \n if (terms.length === 0) return;\n \n var style = document.createElement('style');\n style.textContent = '.userscript-highlight { background: #fbbf24; color: #1a1a2e; padding: 1px 3px; border-radius: 2px; }';\n document.head.appendChild(style);\n \n function highlight(node) {\n if (node.nodeType === 3) { // text node\n var text = node.textContent;\n var found = false;\n terms.forEach(function(term) {\n var regex = new RegExp('(' + term.replace(/[.*+?^${}()|[\\]\\\\]/g, '\\\\') + ')', 'gi');\n if (regex.test(text)) {\n found = true;\n var frag = document.createDocumentFragment();\n var parts = text.split(regex);\n parts.forEach(function(part, i) {\n if (i % 2 === 0) {\n frag.appendChild(document.createTextNode(part));\n } else {\n var span = document.createElement('span');\n span.className = 'userscript-highlight';\n span.textContent = part;\n frag.appendChild(span);\n }\n });\n node.parentNode.replaceChild(frag, node);\n }\n });\n } else if (node.nodeType === 1 && node.childNodes) { // element\n var skipTags = ['SCRIPT', 'STYLE', 'NOSCRIPT', 'TEXTAREA', 'INPUT', 'SELECT'];\n if (!skipTags.includes(node.tagName)) {\n Array.from(node.childNodes).forEach(highlight);\n }\n }\n }\n \n highlight(document.body);\n \n // Re-highlight on dynamic content\n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1 || node.nodeType === 3) highlight(node);\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Highlight Search Terms");
}
} catch(__e) { console.warn('[Userscript:Highlight Search Terms]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
BranchesTags
Repository files navigation
Solidity Coding Test
Arbitrager
This exercise is designed to test a programmer's understanding of the Solidity language, ability to research and integrate other protocols, and their understanding of both traditional finance and DeFi concepts such as arbitrage, decentralized exchanges, and automated market makers.
Main Task
Modify the Arbitrager.sol contract to handle arbitraging a WETH/token pair between two exchanges that use Uniswap V2 contracts. The function needs to check that the call was profitable and return the ETH back to the sender or revert otherwise.
Additional Challenges
The following challenges are not required but they help us understand your coding skills and ability to handle architectural changes to the smart contracts.
  1. Modify the contract to support arbitrary token pairs.
  2. Make the contract ownable and then have the contract use its own funds for trading. Provide profit-sharing incentives to users who call the arbitrage() function.
  3. Add support for gas station network and use profits to pay for the gas costs.
  4. Integrate flash loans to improve the capital efficiency of the contract.
Setup
Duplicate Repository
  • Import this repository as a private repo. Note that this is different from forking.
  • Go to Settings -> Actions -> General and select Allow all actions and reusable workflows. This will allow the Github workflow that is part of the repo to run in your pull request so you can get feedback about your contract from CI.
  • Give read access to Adam and Michalis.
  • Push your solution in a new branch and open a pull request in your repo to your main branch.
Install
yarn

Compile
yarn compile

Test
yarn test

About
No description, website, or topics provided.
Resources
Readme
Activity
Custom properties
Stars
0 stars
Watchers
0 watching
Forks
0 forks
Report repository
Releases
Packages
Contributors
Languages

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Strip utm_, fbclid, gclid, etc. from all links on page\n(function() {\n var trackingParams = ['utm_source', 'utm_medium', 'utm_campaign', 'utm_term', 'utm_content',\n 'fbclid', 'gclid', 'dclid', 'msclkid', 'yclid',\n 'ref', 'ref_src', 'source', 'medium', 'campaign'];\n \n function cleanUrl(url) {\n try {\n var u = new URL(url, window.location.origin);\n var changed = false;\n trackingParams.forEach(function(p) {\n if (u.searchParams.has(p)) {\n u.searchParams.delete(p);\n changed = true;\n }\n });\n return changed ? u.toString() : url;\n } catch (e) {\n return url;\n }\n }\n \n function cleanLinks() {\n document.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n \n cleanLinks();\n \n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1) {\n if (node.tagName === 'A') cleanLinks();\n node.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Remove Tracking Parameters from Links");
}
} catch(__e) { console.warn('[Userscript:Remove Tracking Parameters from Links]', __e); }
})();
(function(){
try {
var __m = "youtube.com";
var __re = new RegExp('^' + "youtube\\.com" + '

Skip to content
BranchesTags
Repository files navigation
Solidity Coding Test
Arbitrager
This exercise is designed to test a programmer's understanding of the Solidity language, ability to research and integrate other protocols, and their understanding of both traditional finance and DeFi concepts such as arbitrage, decentralized exchanges, and automated market makers.
Main Task
Modify the Arbitrager.sol contract to handle arbitraging a WETH/token pair between two exchanges that use Uniswap V2 contracts. The function needs to check that the call was profitable and return the ETH back to the sender or revert otherwise.
Additional Challenges
The following challenges are not required but they help us understand your coding skills and ability to handle architectural changes to the smart contracts.
  1. Modify the contract to support arbitrary token pairs.
  2. Make the contract ownable and then have the contract use its own funds for trading. Provide profit-sharing incentives to users who call the arbitrage() function.
  3. Add support for gas station network and use profits to pay for the gas costs.
  4. Integrate flash loans to improve the capital efficiency of the contract.
Setup
Duplicate Repository
  • Import this repository as a private repo. Note that this is different from forking.
  • Go to Settings -> Actions -> General and select Allow all actions and reusable workflows. This will allow the Github workflow that is part of the repo to run in your pull request so you can get feedback about your contract from CI.
  • Give read access to Adam and Michalis.
  • Push your solution in a new branch and open a pull request in your repo to your main branch.
Install
yarn

Compile
yarn compile

Test
yarn test

About
No description, website, or topics provided.
Resources
Readme
Activity
Custom properties
Stars
0 stars
Watchers
0 watching
Forks
0 forks
Report repository
Releases
Packages
Contributors
Languages

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Auto-enable theater mode on YouTube\n(function() {\n function tryTheater() {\n var btn = document.querySelector('button[aria-label=\"Theater mode\"], ytd-player #player button[title=\"Theater mode\"]');\n if (btn && !btn.classList.contains('activated')) {\n btn.click();\n }\n }\n \n // Try immediately\n tryTheater();\n \n // Try after navigation (SPA)\n var lastUrl = location.href;\n setInterval(function() {\n if (location.href !== lastUrl) {\n lastUrl = location.href;\n setTimeout(tryTheater, 500);\n }\n }, 1000);\n \n // Also try on player load\n var observer = new MutationObserver(tryTheater);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "YouTube Theater Mode Default");
}
} catch(__e) { console.warn('[Userscript:YouTube Theater Mode Default]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
BranchesTags
Repository files navigation
Solidity Coding Test
Arbitrager
This exercise is designed to test a programmer's understanding of the Solidity language, ability to research and integrate other protocols, and their understanding of both traditional finance and DeFi concepts such as arbitrage, decentralized exchanges, and automated market makers.
Main Task
Modify the Arbitrager.sol contract to handle arbitraging a WETH/token pair between two exchanges that use Uniswap V2 contracts. The function needs to check that the call was profitable and return the ETH back to the sender or revert otherwise.
Additional Challenges
The following challenges are not required but they help us understand your coding skills and ability to handle architectural changes to the smart contracts.
  1. Modify the contract to support arbitrary token pairs.
  2. Make the contract ownable and then have the contract use its own funds for trading. Provide profit-sharing incentives to users who call the arbitrage() function.
  3. Add support for gas station network and use profits to pay for the gas costs.
  4. Integrate flash loans to improve the capital efficiency of the contract.
Setup
Duplicate Repository
  • Import this repository as a private repo. Note that this is different from forking.
  • Go to Settings -> Actions -> General and select Allow all actions and reusable workflows. This will allow the Github workflow that is part of the repo to run in your pull request so you can get feedback about your contract from CI.
  • Give read access to Adam and Michalis.
  • Push your solution in a new branch and open a pull request in your repo to your main branch.
Install
yarn

Compile
yarn compile

Test
yarn test

About
No description, website, or topics provided.
Resources
Readme
Activity
Custom properties
Stars
0 stars
Watchers
0 watching
Forks
0 forks
Report repository
Releases
Packages
Contributors
Languages

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Remove or un-stick sticky/fixed headers that block content\n(function() {\n function unstick() {\n document.querySelectorAll('header, nav, [role=\"banner\"], .header, .navbar, .sticky, .fixed-top, [style*=\"position: fixed\"], [style*=\"position:sticky\"]').forEach(function(el) {\n if (el.style.position === 'fixed' || el.style.position === 'sticky' || \n getComputedStyle(el).position === 'fixed' || getComputedStyle(el).position === 'sticky') {\n el.style.position = 'static';\n el.style.top = 'auto';\n el.style.zIndex = 'auto';\n }\n });\n }\n \n unstick();\n \n var observer = new MutationObserver(unstick);\n observer.observe(document.body, { childList: true, subtree: true, attributes: true, attributeFilter: ['style', 'class'] });\n})();", "Kill Sticky Headers");
}
} catch(__e) { console.warn('[Userscript:Kill Sticky Headers]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
BranchesTags
Repository files navigation
Solidity Coding Test
Arbitrager
This exercise is designed to test a programmer's understanding of the Solidity language, ability to research and integrate other protocols, and their understanding of both traditional finance and DeFi concepts such as arbitrage, decentralized exchanges, and automated market makers.
Main Task
Modify the Arbitrager.sol contract to handle arbitraging a WETH/token pair between two exchanges that use Uniswap V2 contracts. The function needs to check that the call was profitable and return the ETH back to the sender or revert otherwise.
Additional Challenges
The following challenges are not required but they help us understand your coding skills and ability to handle architectural changes to the smart contracts.
  1. Modify the contract to support arbitrary token pairs.
  2. Make the contract ownable and then have the contract use its own funds for trading. Provide profit-sharing incentives to users who call the arbitrage() function.
  3. Add support for gas station network and use profits to pay for the gas costs.
  4. Integrate flash loans to improve the capital efficiency of the contract.
Setup
Duplicate Repository
  • Import this repository as a private repo. Note that this is different from forking.
  • Go to Settings -> Actions -> General and select Allow all actions and reusable workflows. This will allow the Github workflow that is part of the repo to run in your pull request so you can get feedback about your contract from CI.
  • Give read access to Adam and Michalis.
  • Push your solution in a new branch and open a pull request in your repo to your main branch.
Install
yarn

Compile
yarn compile

Test
yarn test

About
No description, website, or topics provided.
Resources
Readme
Activity
Custom properties
Stars
0 stars
Watchers
0 watching
Forks
0 forks
Report repository
Releases
Packages
Contributors
Languages

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Universal Dark Mode - works on any site\n(function() {\n var enabled = true;\n \n function applyDarkMode() {\n if (!enabled) return;\n \n // Create style element if it doesn't exist\n var style = document.getElementById('universal-dark-mode-style');\n if (!style) {\n style = document.createElement('style');\n style.id = 'universal-dark-mode-style';\n document.head.appendChild(style);\n }\n \n // Dark mode CSS - inverts colors but preserves images/video\n style.textContent = '\n /* Invert everything except media */\n html {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #1a1a2e !important;\n }\n \n /* Restore images, videos, iframes, canvas */\n img, video, iframe, canvas, svg, picture, [style*=\"background-image\"] {\n filter: invert(1) hue-rotate(180deg) !important;\n }\n \n /* Preserve specific elements that should not be inverted */\n .no-dark-mode, .no-dark-mode *,\n [data-theme=\"light\"], [data-theme=\"light\"],\n .ace_editor, .ace_editor *,\n .CodeMirror, .CodeMirror *,\n .monaco-editor, .monaco-editor *,\n .markdown-body pre, .markdown-body pre *,\n .highlight, .highlight *,\n pre code, pre code * {\n filter: none !important;\n }\n \n /* Fix common UI elements */\n .modal, .popup, .dropdown-menu, .tooltip, .popover {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #2d2d44 !important;\n border-color: #444 !important;\n }\n \n /* Scrollbars */\n ::-webkit-scrollbar { background: #1a1a2e !important; }\n ::-webkit-scrollbar-thumb { background: #444 !important; }\n ::-webkit-scrollbar-thumb:hover { background: #555 !important; }\n \n /* Selection */\n ::selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ::-moz-selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ';\n }\n \n function removeDarkMode() {\n var style = document.getElementById('universal-dark-mode-style');\n if (style) style.remove();\n }\n \n // Toggle with Alt+Shift+D\n document.addEventListener('keydown', function(e) {\n if (e.altKey && e.shiftKey && e.key === 'D') {\n e.preventDefault();\n enabled = !enabled;\n if (enabled) {\n applyDarkMode();\n console.log('[Universal Dark Mode] Enabled');\n } else {\n removeDarkMode();\n console.log('[Universal Dark Mode] Disabled');\n }\n }\n });\n \n // Apply on load\n applyDarkMode();\n \n // Re-apply on dynamic content\n var observer = new MutationObserver(function(mutations) {\n if (enabled && !document.getElementById('universal-dark-mode-style')) {\n applyDarkMode();\n }\n });\n observer.observe(document.head, { childList: true });\n \n console.log('[Universal Dark Mode] Loaded - Press Alt+Shift+D to toggle');\n})();", "Universal Dark Mode");
}
} catch(__e) { console.warn('[Userscript:Universal Dark Mode]', __e); }
})();
})();

Skip to content
BranchesTags
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Solidity Coding Test
Arbitrager
This exercise is designed to test a programmer's understanding of the Solidity language, ability to research and integrate other protocols, and their understanding of both traditional finance and DeFi concepts such as arbitrage, decentralized exchanges, and automated market makers.
Main Task
Modify the Arbitrager.sol contract to handle arbitraging a WETH/token pair between two exchanges that use Uniswap V2 contracts. The function needs to check that the call was profitable and return the ETH back to the sender or revert otherwise.
Additional Challenges
The following challenges are not required but they help us understand your coding skills and ability to handle architectural changes to the smart contracts.
  1. Modify the contract to support arbitrary token pairs.
  2. Make the contract ownable and then have the contract use its own funds for trading. Provide profit-sharing incentives to users who call the arbitrage() function.
  3. Add support for gas station network and use profits to pay for the gas costs.
  4. Integrate flash loans to improve the capital efficiency of the contract.
Setup
Duplicate Repository
  • Import this repository as a private repo. Note that this is different from forking.
  • Go to Settings -> Actions -> General and select Allow all actions and reusable workflows. This will allow the Github workflow that is part of the repo to run in your pull request so you can get feedback about your contract from CI.
  • Give read access to Adam and Michalis.
  • Push your solution in a new branch and open a pull request in your repo to your main branch.
Install
yarn

Compile
yarn compile

Test
yarn test

About
No description, website, or topics provided.
Resources
Readme
Activity
Custom properties
Stars
0 stars
Watchers
0 watching
Forks
0 forks
Report repository
Releases
Packages
Contributors
Languages