求助::为啥这种做法是错的
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求助::为啥这种做法是错的
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wusihao1931楼主2022/10/18 12:18
#include <queue>
#include <cstdio>
#include <cstring>
#include <iostream>

#define x first
#define y second

using namespace std;

typedef pair<int, int> PII;

const int N = 1010, M = N * N + N;

int n;
int w[N];
int cnt[N];
bool st[N];
int dist[N];
int h[N], e[M], ne[M], idx;

void add(int a, int b)
{
    e[idx] = b;
    ne[idx] = h[a];
    h[a] = idx;
    idx ++ ;
}

void dijkstra(int s)
{
    priority_queue<PII, vector<PII>, greater<PII>> q;
    memset(dist, 0x3f, sizeof dist);
    cnt[s] = 1;
    dist[s] = 0;
    q.push({dist[s], s});
    
    while (q.size())
    {
        auto t = q.top();
        q.pop();
        
        int ver = t.y;
        
        if (st[ver]) continue;
        st[ver] = true;
        
        for (int i = h[ver]; i != - 1; i = ne[i])
        {
            int j = e[i];
            if (dist[j] > dist[ver] + w[j])
            {
                dist[j] = dist[ver] + w[j];

                cnt[j] = cnt[ver];
                q.push({dist[j], j});
            }
            else if (dist[j] == dist[ver] + w[j]) 
            {
                
                cnt[j] += cnt[ver];
            }
        }
    }
}

int main()
{
    cin >> n;
    memset(h, -1, sizeof h);
    for (int i = 0; i < n; i ++ ) scanf("%d", &w[i]);
    
    int a, b, c;
    while (scanf("%d %d %d", &a, &b, &c) != EOF) 
    {
        add(a, b), add(b, a);
        add(b, c), add(c, b);
    }

    
    for (int i = 0; i < n; i ++ ) add(n, i);
    
    dijkstra(n);
    
    cout << dist[0] << " " << cnt[0] << endl;
    
    return 0;
}
2022/10/18 12:18
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