Crowd Control(输出不在最大值最小化的最短路上的边)

#include <iostream>
#include <cstdio>
#include <sstream>
#include <cstring>
#include <map>
#include <cctype>
#include <set>
#include <vector>
#include <stack>
#include <queue>
#include <algorithm>
#include <cmath>
#include <bitset>
#define rap(i, a, n) for(int i=a; i<=n; i++)
#define rep(i, a, n) for(int i=a; i<n; i++)
#define lap(i, a, n) for(int i=n; i>=a; i--)
#define lep(i, a, n) for(int i=n; i>a; i--)
#define rd(a) scanf("%d", &a)
#define rlld(a) scanf("%lld", &a)
#define rc(a) scanf("%c", &a)
#define rs(a) scanf("%s", a)
#define MOD 2018
#define LL long long
#define ULL unsigned long long
#define Pair pair<int, int>
#define mem(a, b) memset(a, b, sizeof(a))
#define _  ios_base::sync_with_stdio(0),cin.tie(0)
//freopen("1.txt", "r", stdin);
using namespace std;
const int maxn = 10010, INF = 0x7fffffff;
int head[maxn], cnt;
int d[maxn], vis[maxn], pre[maxn], ans[maxn];
int s, t, n, m;
vector<int> f;
vector<int> g;
struct node
{
    int u, v, c, next;
}Node[maxn];

void add_(int u, int v, int c)
{
    Node[cnt].u = u;
    Node[cnt].v = v;
    Node[cnt].c = c;
    Node[cnt].next = head[u];
    head[u] = cnt++;
}

void add(int u, int v, int c)
{
    add_(u, v, c);
    add_(v, u, c);
}

void init()
{
    mem(head, -1);
    cnt = 0;
}

void spfa()
{
    mem(d, 0);
    queue<int> Q;
    Q.push(s);
    vis[s] = 1;
    d[s] = INF;
    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.c))
            {
                d[e.v] = min(d[u], e.c);
                pre[e.v] = u;
                if(!vis[e.v])
                {
                    vis[e.v] = 1;
                    Q.push(e.v);
                }
            }
        }
    }
}
void dfs1(int u)
{
    f.push_back(u);
    vis[u] = 1;
    if(u == 0) return;
    dfs1(pre[u]);
}

void dfs2(int n)
{
    int x = f[n];
    if(n == 0)
    {
        for(int i=0; i<cnt; i+=2)
            if(Node[i].u == x && Node[i].v != f[n+1] || Node[i].v == x && Node[i].u != f[n+1]) g.push_back(i/2);
        return;
    }

    for(int i=0; i<cnt; i+=2)
    {
        if(Node[i].u == x && Node[i].v != f[n+1] && Node[i].v != f[n-1] || Node[i].v == x && Node[i].u != f[n+1] && Node[i].u != f[n-1]) g.push_back(i/2);
    }
    dfs2(n-1);

}

int main()
{
    init();
    scanf("%d%d", &n, &m);
    int u, v, c;
    for(int i=0; i<m; i++)
    {
        scanf("%d%d%d", &u, &v, &c);
        add(u, v, c);
    }
    s = 0; t = n-1;
    spfa();
    mem(vis, 0);
    dfs1(t);
    dfs2(f.size() - 1);
    sort(g.begin(), g.end());
    g.erase(unique(g.begin(), g.end()), g.end());
    for(int i=0; i<g.size(); i++)
    {
        if(i != 0)
            printf(" ");
        printf("%d", g[i]);
    }
    if(g.size() == 0) printf("none");
    printf("\n");

    return 0;
}