Dijkstra算法（堆优化）

Dijkstra算法时间复杂度（mlogn）

#include <iostream>
#include <string>
#include <cstdio>
#include <algorithm>
#include <cstring>
#include <cmath>
#include <queue>
#include <functional>
#include <map>
#include <set>
#include <stack>
#define FT(a, b) memset(a, b, sizeof(a))
#define FAT(a) memset(a, 0, sizeof(a))
using namespace std;
typedef long long ll;
const int M = 1e5 + 10;
const int INF = 0x3f3f3f3f;
struct node
{
    int a, d;
    bool operator<(const node &x) const
    {
        return x.d < d;
    }
};
priority_queue<node> q;
int n, m, dis[M], e[M], ne[M], h[M], w[M], idx;
bool vis[M];
void add(int a, int b, int c)
{
    e[idx] = b, w[idx] = c, ne[idx] = h[a], h[a] = idx++;
}
void dijkstra()
{
    FT(dis, INF);
    FAT(vis);
    dis[1] = 0;
    q.push({1, 0});
    node n1;
    while (!q.empty())
    {
        n1 = q.top();
        q.pop();
        if (!vis[n1.a])
        {
            vis[n1.a] = 1;
            for (int i = h[n1.a]; i != -1; i = ne[i])
            {
                int j = e[i];
                if (dis[j] > n1.d + w[i])
                {
                    dis[j] = n1.d + w[i];
                    q.push({j, dis[j]});
                }
            }
        }
    }
}
int main()
{
#ifdef ONLINE_JUDGE
#else
    freopen("f:\\code\\c++\\in.txt", "r", stdin);
#endif
    while (~scanf("%d%d", &n, &m))
    {
        FT(h, -1);
        idx = 0;
        for (int i = 0; i < m; i++)
        {
            int a, b, c;
            scanf("%d%d%d", &a, &b, &c);
            add(a, b, c);
        }
        dijkstra();
        printf("%d\n", dis[n]==INF?-1:dis[n]);
    }
    return 0;
}