题解 | #小木乃伊到我家#

写着道题目气死我自己，一直没有注意是无向图题目，WA了半天....... 来个纯数组的Dijsktra，

#include <iostream>
#include <algorithm>
#include <queue>
#include <cstring>

using namespace std;
const int N = 4e5 + 10;
typedef pair<int, int> PII;
int n, m;
int dist[N], w[N];
int h[N],e[N],ne[N],idx;
priority_queue<PII, vector<PII>, greater<PII>> q;
bool st[N];

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

int dijsktra() {
    memset(dist, 0x3f, sizeof dist);
    
    q.push({0, 1});
    
    dist[1] = 0;
    
    while (q.size()) {
        auto t = q.top();
        
        q.pop();
        
        int distance = t.first, k = t.second;
        if (st[k]) continue;
        st[k] = true;
        
        for (int i = h[k]; ~i; i = ne[i]) {
            int j = e[i];
            if (!st[j] && dist[j] > distance + w[i]) {
                dist[j] = distance + w[i];
                q.push({dist[j], j});
            }
        }
    }
    
    if (dist[n] == 0x3f3f3f3f) return -1;
    return dist[n];
}

int main()
{
    ios::sync_with_stdio(false),cin.tie(0),cout.tie(0);
    cin >> n >> m;
    memset(h, -1, sizeof h);
    while (m--) {
        int a, b, c;
        cin >> a >> b >> c;
        add(a, b, c);
        add(b, a, c);
    }
    
    int t = dijsktra();
    if (t == -1) cout << "qwb baka";
    else cout << t;
    return 0;
}