algorithm/binary_trie.cpp at main · CAEL0/algorithm · GitHub

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// BOJ 13505 두 수 XOR

#include<bits/stdc++.h>
#defineszsize()
#definebkback()
#definefi first
#definese second

usingnamespacestd;
typedeflonglong ll;
typedef pair<int, int> pii;

structNode {
int zero = -1;
int one = -1;
};

structTrie {
 vector<Node> nodes;

Trie() { nodes.push_back(Node()); }

voidinsert(int cur, int x, int bit) {
if (bit == 0)
return;

if (x & bit) {
if (nodes[cur].one == -1) {
 nodes[cur].one = nodes.sz;
 nodes.push_back(Node());
 }

insert(nodes[cur].one, x, bit >> 1);
 } else {
if (nodes[cur].zero == -1) {
 nodes[cur].zero = nodes.sz;
 nodes.push_back(Node());
 }

insert(nodes[cur].zero, x, bit >> 1);
 }
 }

intminimum(int cur, int x, int bit) {
if (bit == 0)
return0;

if (x & bit) {
if (nodes[cur].one == -1)
return bit + minimum(nodes[cur].zero, x, bit >> 1);

returnminimum(nodes[cur].one, x, bit >> 1);
 }

if (nodes[cur].zero == -1)
return bit + minimum(nodes[cur].one, x, bit >> 1);

returnminimum(nodes[cur].zero, x, bit >> 1);
 }

intmaximum(int cur, int x, int bit) {
if (bit == 0)
return0;

if (x & bit) {
if (nodes[cur].zero == -1)
returnmaximum(nodes[cur].one, x, bit >> 1);

return bit + maximum(nodes[cur].zero, x, bit >> 1);
 }

if (nodes[cur].one == -1)
returnmaximum(nodes[cur].zero, x, bit >> 1);

return bit + maximum(nodes[cur].one, x, bit >> 1);
 }
};

intmain() {
ios::sync_with_stdio(0);
 cin.tie(0);
 cout.tie(0);

int n;
 cin >> n;

 vector<int> v(n);
for (int i = 0; i < n; i++)
 cin >> v[i];

 Trie trie;
int bit = (1 << 29);

for (int x : v)
 trie.insert(0, x, bit);

int ans = 0;
for (int x : v)
 ans = max(ans, trie.maximum(0, x, bit));

 cout << ans;
}