Floyd 求最小环模板

#include <bits/stdc++.h>
using namespace std;
using ll = long long;

const int N = 110;
ll dis[N][N], w[N][N];
int n, m, u, v, f;
ll ans = LLONG_MAX;

void floyd() {
	for (int k = 1; k <= n; k++) {
		for (int i = 1; i < k; i++) {
			for (int j = i + 1; j < k; j++) {
				ans = min(ans, dis[i][j] + w[j][k] + w[k][i]);
			} 
		}
		
		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]);
			} 
		}
	}
}

int main() {
	cin >> n >> m;
	
	for (int i = 1; i <= n; i++) {
		for (int j = 1; j <= n; j++) {
			if (i != j) w[i][j] = dis[i][j] = INT_MAX;
		}
	}
	
	for (int i = 1; i <= m; i++) {
		cin >> u >> v >> f;
		dis[u][v] = dis[v][u] = w[u][v] = w[v][u] = f;
	}

	floyd();
	
	if (ans >= INT_MAX) {
		cout << "No solution.";
	} else {
		cout << ans;
	}

	return 0;
}
```cpp