题目链接：Dijkstra求最短路 II
#include <iostream>
#include <cstring>
#include <algorithm>
#include <vector>
#include <queue>using namespace std;typedef pair<int, int> PII;const int N = 150010;int n, m;
int h[N], w[N], e[N], ne[N], idx;int dist[N];
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 dijkstra()
{memset(dist, 0x3f, sizeof dist);dist[1] = 0;priority_queue<PII, vector<PII>, greater<PII>> heap;// {0, 1} 距离为0 编号为1heap.push({0, 1});while(heap.size()){// 小根堆的堆顶元素就是最小元素(根据距离排列)auto t = heap.top();heap.pop();int distance = t.first, ver = t.second;if(!st[ver]){st[ver] = true;// 更新其他点for(int i = h[ver]; i != -1; i = ne[i]){int j = e[i];if(dist[j] > distance + w[i]){dist[j] = distance + w[i];heap.push({dist[j], j});}}}}if(dist[n] == 0x3f3f3f3f) return -1;return dist[n];
}int main()
{cin >> n >> m;memset(h, -1, sizeof h);for(int i = 0; i < m; i ++){int a, b, c;cin >> a >> b >>c;add(a, b, c);}cout << dijkstra() << endl;return 0;
}
