树的根与遍历

#include <bits/stdc++.h>
using namespace std;

int main() {
vector<vector<int>>g{{1,2},{0,3},{0},{1}};
vector<int>depth(4),size(4,1);
function<void(int,int)>dfs=[&](int u,int p){for(int v:g[u])if(v!=p){depth[v]=depth[u]+1;dfs(v,u);size[u]+=size[v];}};
dfs(0,-1);cout<<depth[3]<<" "<<size[1];
}

#include <bits/stdc++.h>
using namespace std;

int main() {
vector<vector<int>>g{{1,2},{0,3},{0},{1}};
vector<int>depth(4),size(4,1);
function<void(int,int)>dfs=[&](int u,int p){for(int v:g[u])if(v!=p){depth[v]=depth[u]+1;dfs(v,u);size[u]+=size[v];}};
dfs(0,-1);cout<<depth[3]<<" "<<size[1];
}