pat1094 The Largest Generation

题意：输入一颗树，问那个高度的节点数量最多，并输出节点数以及高度。

思路：dfs计算高度，计数一下即可。

代码

#include <iostream>
#include <cstdio>
#include <cstring>
#include <cmath>
#include <algorithm>
#include <vector>

using namespace std;

const int MAX_N = 110;

int N, M, k, x, y, rt;
vector<int> G[MAX_N];
int vis[MAX_N], level[MAX_N];
int cnt[MAX_N], lev, num;

void dfs(int rt) {
    for (int i = 0; i < G[rt].size(); i++) {
        level[G[rt][i]] = level[rt] + 1;
        dfs(G[rt][i]);
    }
}

int main() {
    // freopen("in.txt", "r", stdin);
    // freopen("out.txt", "w", stdout);
    scanf("%d %d", &N, &M);
    for (int i = 0; i < M; i++) {
        scanf("%d %d", &x, &k);
        for (int j = 0; j < k; j++) {
            scanf("%d", &y);
            vis[y] = 1;
            G[x].push_back(y);
        }
    }
    for (int i = 1; i <= N; i++) if (!vis[i]) {rt = i; break;}
    dfs(rt);
    for (int i = 1; i <= N; i++) cnt[level[i]]++;
    for (int i = 0; i < N; i++) {
        if (cnt[i] > num) {
            lev = i; num = cnt[i];
        }
    }
    printf("%d %d\n", num, lev+1);
    return 0;
}