poj 2531

暴力搜索 因为数据太弱 并不想去加什么剪枝

#include <iostream>#include <cstring>#include <vector>#include <algorithm>using namespace std;#define met(a, b) memset(a, b, sizeof(a))const int N = 25;int g[N][N], vis[N], n, ans;void dfs (int k, int sum);int main (){    while (cin >> n)    {        for (int i=0; i<n; i++)            for (int j=0; j<n; j++)                cin >> g[i][j];        ans = 0;        met (vis, 0);        vis[0] = 1;        dfs (0, 0);        cout << ans << endl;    }    return 0;}void dfs (int k, int sum){    int x = sum;    for (int i=0; i<n; i++)    {        if (vis[i]) x -= g[k][i];        else x += g[k][i];    }    if (x > ans) ans = x;    for (int i=k+1; i<n; i++)    {        if (!vis[i])        {            vis[i] = 1;            dfs (i, x);            vis[i] = 0;        }    }}