HDU-1874-暢通工程續（最短路，FLOYD）

題目連接

題意：最短路徑Floyd裸題

注意：數組初始化mp[i][i] = 0;還有兩個點之間可能有多條路

#include<cstdio>
#include<cmath>
#include<cstring>
#include<algorithm>
#include<iostream>
#include<time.h>
#include<set>
#include<stack>
#include<vector>
#include<map>

#define pi acos(-1)
#define maxn 111111
#define maxm 11111
#define INF 0x3F3F3F3F
#define eps 1e-8

#define pb push_back

#define mem(a) memset(a,0,sizeof a)

using namespace std;

const long long mod = 1000000007;
/**lyc**/
int n, m;
int s, t;
int mp[1111][1111];
void init(void) {
    memset(mp, INF, sizeof mp);
    for (int i = 0; i <= n; i++) {
        mp[i][i] = 0;
    }
}
void Floyd() {
    for (int k = 0; k < n; k++) {
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < n; j++) {
                mp[i][j] = min(mp[i][j], mp[i][k] + mp[k][j]);
            }
        }
    }
}
int main() {
    //init();
    while (scanf("%d%d", &n, &m) != EOF) {
        init();
        int a, b, x;
        for (int i = 1; i <= m; i++) {
            scanf("%d%d%d", &a, &b, &x);
            if(x < mp[a][b])
                mp[a][b] = mp[b][a] = x;
        }
        scanf("%d%d", &s, &t);
        Floyd();
        if (mp[s][t] != INF) {
            printf("%d\n", mp[s][t]);
        }
        else {
            printf("-1\n");
        }

    }
    return 0;
}