动态规划练习 10

[code]#include <iostream>

#include <string>

#include <memory.h>

using namespace std;

bool dp[201][201];

// Recursion version.

bool check_yes(const string &a, size_t i, const string &b, size_t j, const string &c, size_t k)

{

if (k >= c.size())

{

return true;

}

bool ret1 = false, ret2 = false;

if (i < a.size() && c[k] == a[i])

{

ret1 = check_yes(a, i + 1, b, j, c, k + 1);

}

if (j < b.size() && c[k] == b[j])

{

ret2 = check_yes(a, i, b, j + 1, c, k + 1);

}

return ret1 || ret2;

}

int main(int argc, char **argv)

{

int n;

string a, b, c;

cin >> n;

for (int m = 1; m <= n; ++m)

{

cin >> a >> b >> c;

// Recursion version.

// cout << check_yes(a, 0, b, 0, c, 0) << endl;

// dp[i][j] = (dp[i - 1][j] && a[i - 1] == c[i + j - 1]) ||

//            (dp[i][j - 1] && b[j - 1] == c[i + j - 1]);

memset(dp, 0, sizeof(dp));

dp[0][0] = true;

for (size_t i = 1; i <= a.size(); ++i)

{

dp[i][0] = dp[i - 1][0] && a[i - 1] == c[i - 1];

}

for (size_t j = 1; j <= b.size(); ++j)

{

dp[0][j] = dp[0][j - 1] && b[j - 1] == c[j - 1];

}

for (size_t i = 1; i <= a.size(); ++i)

{

    for (size_t j = 1; j <= b.size(); ++j)

{

dp[i][j] = (dp[i - 1][j] && a[i - 1] == c[i + j - 1])

|| (dp[i][j - 1] && b[j - 1] == c[i + j - 1]);

}

}

cout << "Data set " << m << ": " <<

(dp[a.size()][b.size()] ? "yes" : "no") << endl;

}

return 0;

}