1004. Counting Leaves (30) 树的dfs

#include <iostream>
#include <vector>
#include <cmath>
using namespace std;
//大意：统计每一层叶子结点的个数 并输出
//根节点id固定为01
//思路：树的模拟套路

vector<int> v[100];
int level[100] = {0};
int maxdepth = 0;

void dfs(int index, int depth){//思路：遇到叶子结点就把level[depth]++
    if (v[index].size() == 0) {
        level[depth]++;
        if(depth > maxdepth) maxdepth = depth;
        return;
    }
    for (int i = 0; i < v[index].size(); i++) {
        dfs(v[index][i], depth + 1);
    }

}

int main(){
    int n, m;//结点个数  非非叶子结点的个数
    cin >> n >> m;
    for (int i = 0; i < m; i++) {
        int f, c;
        cin >> f >> c;
        for (int i = 0; i < c; i++) {
            int k;
            cin >> k;
            v[f].push_back(k);//f是k的父结点
        }
    }
    dfs(1, 0);
    for (int i = 0; i <= maxdepth; i++) {
        printf("%d%c", level[i], i == maxdepth ? '\n' : ' ');
    }

    return 0;
}