Heavy Transportation spfa算法

题目题意：这道题的意思和 Frogger 很像。求所有路径中每个路径最小的一段道路，这些道路组成一个集合，再求这个集合中最大的数。
思路：`
核心代码

for(int i=head[n];i!=-1;i=Node[i].next){
Node e=Node[i];
if(d[e.v]<min(d[u],e.d){
d[e.v]=min(d[u],e.d);
}`

#include <iostream>
#include <cstdio>
#include <cstring>
#include <queue>
#define mem(a,b) memset(a,b,sizeof(a))
using namespace std;
const int maxn = 100100, INF = 0xfffffff;
int head[maxn], vis[maxn], d[maxn];
int n, m;
struct node {
    int u, v, d, next;
} Node[maxn];
void add(int u, int v, int d, int i) {
    Node[i].u = u;
    Node[i].v = v;
    Node[i].d = d;
    Node[i].next = head[u];
    head[u] = i;
}
void spfa(int s) {
    mem(d, 0);
    d[s] = INF;
    mem(vis, 0);
    queue<int> Q;
    Q.push(s);
    vis[s] = 1;
    while(!Q.empty()) {
        int u = Q.front();
        Q.pop();
        vis[u] = 0;
        for(int i = head[u]; i != -1; i = Node[i].next) {
            node e = Node[i];
            if(d[e.v] < min(d[u], e.d)) {
                d[e.v] = min(d[u], e.d);
                if(!vis[e.v]) {
                    Q.push(e.v);
                    vis[e.v] = 1;
                }
            }
        }
    }
}
int main() {
    int cnt = 0;
    int T;
    scanf("%d", &T);
    while(T--) {
        mem(head, -1);
        scanf("%d%d", &n, &m);
        int ans = 0;
        for(int i = 1; i <= m; i++) {
            int u, v, d;
            scanf("%d%d%d", &u, &v, &d);
            add(u, v, d, ans++);
            add(v, u, d, ans++);
        }
        spfa(1);
        printf("Scenario #%d:\n", ++cnt);
        printf("%d\n", d[n]);
        printf("\n");
    }
    return 0;
}