1004 Counting Leaves - dfs、树的处理

思路：前向星+dfs

代码如下：

#include<iostream>
#include<cstdio>
#include<algorithm>
#include<string>
#include<cstring>
#include<queue>
#include<cmath>
#include<set>
#include<sstream>
#define ll long long
using namespace std;
const int N=105,INF=0x3f3f3f3f;
int flag[N],A[N],head[N],cnt=0,shen=0;
struct proc{int to,next;};
proc edge[N];

void addEdge(int from,int to){
    edge[cnt].to=to;
    edge[cnt].next=head[from];
    head[from]=cnt++;
}

void dfs(int now,int dep){
    shen=max(shen,dep);
    int res;
    if(flag[now])res=0;
    else res=1;
    A[dep]+=res;
    for(int i=head[now];i!=-1;i=edge[i].next){
        int dot=edge[i].to;
        dfs(dot,dep+1);
    }
}

int main(){
    int n,m,u,k,a,b;
    scanf("%d%d",&n,&m);
    memset(head,-1,sizeof(head));
    memset(flag,0,sizeof(flag));
    while(m--){
        scanf("%1d%1d",&a,&b);
        u=a*10+b;
        scanf("%d",&k);
        if(k)flag[u]=k;
        while(k--){
            scanf("%1d%1d",&a,&b);
            int tmp=a*10+b;
            addEdge(u,tmp);
        }
    }
    dfs(1,1);
    printf("%d",A[1]);
    for(int i=2;i<=shen;i++)printf(" %d",A[i]);
    printf("\n");
}