python/TangDou/AcWing_TiGao/T3/MiniPathExtend/1134_Bfs.cpp

#include <bits/stdc++.h>
using namespace std;
const int N = 4e5 + 10;
const int MOD = 100003;
int h[N], ne[N], e[N], idx;
void add(int a, int b) {
    e[idx] = b, ne[idx] = h[a], h[a] = idx++;
}

int cnt[N]; // 从顶点1开始，到其他每个点的最短路有几条
int dis[N]; // 最短距离
int n, m;
void bfs() {
    memset(dis, 0x3f, sizeof dis);
    queue<int> q;
    q.push(1);
    cnt[1] = 1; // 从顶点1开始，到顶点1的最短路有1条
    dis[1] = 0; // 距离为0

    while (q.size()) {
        int u = q.front();
        q.pop();
        for (int i = h[u]; ~i; i = ne[i]) {
            int j = e[i];
            if (dis[j] > dis[u] + 1) {
                dis[j] = dis[u] + 1;
                q.push(j);
                cnt[j] = cnt[u];
            } else if (dis[j] == dis[u] + 1)
                cnt[j] = (cnt[j] + cnt[u]) % MOD;
        }
    }
}
int main() {
    memset(h, -1, sizeof h);
    scanf("%d %d", &n, &m);
    while (m--) {
        int a, b;
        scanf("%d %d", &a, &b);
        add(a, b), add(b, a);
    }
    bfs();
    for (int i = 1; i <= n; i++) printf("%d\n", cnt[i]);
    return 0;
}