AcWing 1134. Shortest circuit counting problem solution (shortest circuit)

AcWing 1134. Shortest circuit count
Path weights are 1, use bfs Find the shortest path , In the process of finding cnt The array records the number of routes , Note that when the path lengths are equal , You need to add and update the number of the two paths

#include<bits/stdc++.h>

using namespace std;

const int N = 1e5 + 10, M = 4 * N, INF = 0x3f3f3f3f;

int h[N], e[M], ne[M], idx;
int n, m;
int dist[N];
int cnt[N];
int q[N];
int w[N];

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

void bfs(){
    
	memset(dist, 0x3f, sizeof dist);
	int hh = 0, tt = 0;
	q[0] = 1;
	
	dist[1] = 0;
	cnt[1] = 1;
	
	while(hh <= tt){
    
		int t = q[hh ++ ];
		for(int i = h[t]; ~i; i = ne[i]){
    
			int j = e[i];
			if(dist[j] > dist[t] + 1){
    
				dist[j] = dist[t] + 1;
				cnt[j] = cnt[t];
				q[ ++ tt] = j;
			} 
			else if(dist[j] == dist[t] + 1){
    
				cnt[j] = (cnt[j] + cnt[t]) % 100003;
 			}
		}
	}
	
} 

int main()
{
    
	cin>>n>>m;
	
	memset(h, -1, sizeof h);
	
	while(m -- ){
    
		int a, b;
		cin>>a>>b;
		Add(a, b);
		Add(b, a);
	}
	
	bfs();
	
	for(int i = 1; i <= n; i ++ ){
    
		cout<<cnt[i]<<endl;
	}
	
	return 0;
}