题目描述

输入格式

输出格式

输出一行包含一个整数表示答案。

输入输出样例

解题思路

最短路+二分

AC代码

#include<bits/stdc++.h>
using namespace std;
long long temp,n, Q;
long long f[105][105],min_f[105][105],cut[105],dis[105][105];//cut为减少多少，dis表示减少后的
bool check(long long day)
{temp = 0;//赋初值long long times = day / n;long long now = day%n;for (int i = 1; i <= n; i++){if (i <= now)cut[i] = times + 1;else cut[i] = times;}for (int i = 1; i <= n; i++){for (int j = 1; j <= n; j++){dis[i][j] = max(f[i][j] - cut[i] - cut[j], min_f[i][j]);}}for (int k = 1; k <= n; k++)//Floyd模板for (int i = 1; i <= n; i++)for (int j = 1; j <= n; j++)dis[i][j] = min(dis[i][j], dis[i][k] + dis[k][j]);for (int i = 1; i <= n; i++){for (int j = 1; j <= n; j++){temp += dis[i][j];}}if (temp <= Q)return true;else return false;
}
int main()
{cin >> n>>Q;for (int i = 1; i <= n; i++){for (int j = 1; j <= n; j++){cin >> f[i][j];}}for (int i = 1; i <= n; i++){for (int j = 1; j <= n; j++){cin >> min_f[i][j];}}long long left = 0, right = 1e9,mid;while (left<right){mid = (left + right) / 2;if (check(mid))  right = mid;else left = mid + 1;}if (left == 1e9)cout << "-1" << endl;else cout << left << endl;return 0;
}