20分求助力

#include<iostream>
#include<queue>
#include<cstring>
#define inf 0x3f3f3f3f
#define INF 0x7fffffff
using namespace std;
const int maxn = 1e6;
struct node
{
    int v, next, w;
}edge[maxn];
int cnt;
bool vis[maxn];
int dis[maxn], head[maxn], ans[maxn];
void add(int u, int v, int w)//起点，终点，距离,链式前向星建图 
{
    edge[cnt].w = w;
    edge[cnt].v = v;
    edge[cnt].next = head[u];
    head[u] = cnt;
    cnt++;
}
void dijkstra(int n, int st)
{
    priority_queue<pair<int, int>, vector<pair<int, int>>, greater<pair<int, int>>>q;
    memset(dis, inf, sizeof dis);
    q.push({ 0,st });
    dis[st] = 0;
    ans[st] = 1;
    while (!q.empty())
    {
        pair<int, int> temp = q.top();//记录堆顶，即堆内最小的边并将其弹出 
        q.pop();
        int u = temp.second;//点 
        if (vis[u]) continue;//如果被访问过，就跳过 
        //只用访问一次，从这个点走的边已经全部更新了
        vis[u] = true;//标记 
        for (int i = head[u]; i != -1; i = edge[i].next)//搜索堆顶的所有连边 
        {
            int v = edge[i].v;
            if (dis[v] > dis[u] + edge[i].w)//松弛操作 
            {
                ans[v] = ans[u];
                dis[v] = dis[u] + edge[i].w;
                q.push({ dis[v],v });//把新遍历的点加到堆中 
                //把终点丢进堆里头
            }
            else if (dis[v] == dis[u] + edge[i].w) {
                ans[v] += ans[u];
                ans[v] %= 100003;
            }
        }
    }
    //if(dis[n]==inf) cout<<-1<<endl;
    //else cout<<dis[n]<<endl;
    for (int i = 1; i <= n; i++)
        cout << ans[i] << endl;
}
int main()
{
    int st;
    int n, m, u, v, w;
    cin >> n >> m ;
    memset(head, -1, sizeof(head));
    for (int i = 0; i < m; i++)
    {
        cin >> u >> v ;
        add(u, v, 1);
    }
    dijkstra(n, 1);
    return 0;
}