topcoder/EncodingTrees.cpp at master · arshdeep/topcoder · GitHub

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#include<iostream>
#include<cstdio>
#include<vector>
#include<cassert>
#include<sstream>
#include<set>
#include<unordered_map>
#include<map>
#include<algorithm>
#include<time.h>
usingnamespacestd;
/* https://www.topcoder.com/stat?c=problem_statement&pm=4700&rd=7995 */
#defineSIZEOFSTRINGARRAY(s) sizeof(s)/sizeof(s[0])

classEncodingTrees
{
private:
	string code(vector<long> &dp, int N, int index, char start);
public:
	string getCode(int N, int index);
};

string EncodingTrees::code(vector<long> &dp, int n, int index, char start)
{
if (n == 0)
return"";

size_t idx = 0;
while (index > dp[idx] * dp[n - idx - 1])
	{
 index -= dp[idx] * dp[n - idx - 1];
 ++idx;
	}
int k = (int)dp[n - idx - 1];
int i = (index - 1) / k + 1;
int j = (index - 1) % k + 1;

return (char)(start + idx) + code(dp, idx, i, start) + code(dp, n - idx - 1, j, start + idx + 1);
}

string EncodingTrees::getCode(int N, int index)
{
	vector<long> dp(N + 1);
	dp[0] = 1;

for (size_t i = 1; i <= N; ++i)
	{
for (size_t j = 0; j < i; ++j)
 {
 dp[i] += dp[j] * dp[i - j - 1];
 }
	}

if (index > dp[N])
return"";

returncode(dp, N, index, 'a');
}

voidTEST(int N, int index, string expected)
{
clock_t start, end;
double cpu_time_used;

 start = clock();
 EncodingTrees encodingTrees;

 string result = encodingTrees.getCode(N, index);

assert( result.compare(expected) == 0 );

 end = clock();
 cpu_time_used = ((double) (end - start));
 cout<<"Time taken : "<<cpu_time_used<<endl;
}

vector<string> convert(string *list, int n)
{
 vector<string> ret;

for (int i = 0; i< n; ++i)
 {
 ret.push_back(list[i]);
 }

return ret;
}

voidTest1()
{
TEST(4, 9, "cbad");
TEST(15, 14023, "abcdeohgfniljkm");
TEST(11, 111, "abcdekhfgji");
TEST(19, 2000000000, "");
TEST(19, 1000000000, "nmjgafbcdeihklosrpq");
}

voidTest2()
{
}

voidTest3()
{
}

voidTest4()
{
}

voidTest5()
{
}

voidTest6()
{
}

voidTest7()
{
}

voidTest8()
{
}

voidTest9()
{
}

voidTest10()
{
}

intmain()
{
Test1();
Test2();
Test3();
Test4();
Test5();
Test6();
Test7();
Test8();
Test9();
Test10();
 cout<<"success";

getchar();
return0;
}