最短路-Floyd算法

#include <bits/stdc++.h>
#define inf 0x3f3f3f3f
using namespace std;
int mp[105][105];
int n, m;//n边m点
int st, ed;
int nxt[105][105];
void init()
{
	cin >> n >> m;
	for (int i = 0; i <= n; i++)//初始化
	{
		for (int j = 0; j <= n; j++)
		{
			if (i != j)
				mp[i][j] = mp[j][i] = inf;
		}
	}
	for (int i = 0; i < m; i++)
	{
		int x, y, w;
		cin >> x >> y >> w;
		if (w < mp[x][y])//有些题目坑人给重复路径
			mp[x][y] = mp[y][x] = w;
	}
}
void printpath() {
	while (st != ed) {
		cout << st << "->";
		st = nxt[st][ed];
	}
	cout << ed << endl;
}
void Floyd()
{
	for (int i = 1; i <= n; i++)//初始化路径
		for (int j = 1; j <= n; j++)
			nxt[i][j] = j;

	for (int k = 1; k <= n; k++)
		for (int i = 1; i <= n; i++)
			for (int j = 1; j <= n; j++)
				if (mp[i][k] + mp[k][j] < mp[i][j])
				{
					mp[i][j] = mp[i][k] + mp[k][j];
					nxt[i][j] = nxt[i][k];
				}
}

int main()
{
	init();
	Floyd();
	cin >> st >> ed;
	cout << mp[st][ed] << endl;
	printpath();
	return 0;
}