Submission #941269

#	Time	Username	Problem	Language	Result	Execution time	Memory
941269		WanWan	Beech Tree (IOI23_beechtree)	C++17	0 / 100	1 ms	856 KiB

beechtree

#include "beechtree.h"
#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
void debug_out() {cerr<<endl;}
template <typename Head, typename... Tail>
void debug_out(Head _H, Tail... _T) {cerr<<" "<<to_string(_H);debug_out(_T...);}
#define debug(...) cerr<<"["<<#__VA_ARGS__<<"]:",debug_out(__VA_ARGS__)
#else
#define debug(...)
#endif
const int MAXN = 2005;
const int inf=1000000500ll;
const long long oo =1000000000000000500ll;
const int MOD = (int)1e9+7;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
typedef pair<int,int> pi; 
int par[MAXN];
vector<int>childs[MAXN];
int st[MAXN],en[MAXN];
int TIME;
bool unbalanced[MAXN];
int dep[MAXN];
int tobad[MAXN];
bool child(int par, int child){
    if(st[par]<=st[child] && en[par]>=en[child])return 1;
    return 0;
}
void dfs(int x, int p, int lvl){
    dep[x]=lvl;
    st[x]=TIME++;
    par[x]=p;
    for(auto v:childs[x]){
        dfs(v,x,lvl+1);
        if(tobad[v]){
            tobad[x]=min(tobad[x],tobad[v]);
        }
    }
    if(childs[x].size() == 1){
        unbalanced[x]=1;
        tobad[x]=dep[x];
    }
    en[x]=TIME-1;
}

vector<int> V[MAXN];
void solve(int x){
    V[dep[x]].push_back(x);
    if(childs[x].empty()){
        return;
    }
    if(childs[x].size() == 1){
        solve(childs[x][0]);
        return;
    }
    if(dep[tobad[childs[x][0]]]>dep[tobad[childs[x][1]]]){ // 
        solve(childs[x][0]);
        solve(childs[x][1]);
    } else{
        solve(childs[x][1]);
        solve(childs[x][0]);
    }
}
std::vector<int> beechtree(int n, int M, std::vector<int> P, std::vector<int> C)
{
    vector<int> res=vector<int>(n,0);
    for(int i=0;i<n;i++)tobad[i]=inf;
    for(int i=1;i<n;i++){
        childs[P[i]].push_back(i);
    }
    dfs(0,-1,0);
    for(int i=0;i<n;i++){ // check for this guy
        for(int x=0;x<=n;x++)V[x].clear();
        vector<int>vec;
        for(int x=0;x<n;x++){
            if(child(i,x))vec.push_back(x);
        }
        sort(vec.begin(),vec.end());
        bool bad=0;
        for(auto x:vec){
            if(childs[x].size() > 2){ // literally no way
                bad=1;
                break;
            }
            if(childs[x].size() == 2){
                if(childs[x][0] == childs[x][1]){
                    bad=1;
                    break;
                }
            }
        }
        if(bad){
            res[i]=0;
            continue;
        }
        solve(i);
        // now check if(V) is valid
        vector<int>nodes;
        for(int l=dep[i];l<n;l++){
            for(auto x:V[l]){
                nodes.push_back(x);
            }
        }
        int cnt[2];
        memset(cnt,0,sizeof cnt);
        for(int x=1;x<nodes.size();x++){
            int to=cnt[C[nodes[i]]];
            if(par[nodes[i]] != nodes[to]){
                bad=1;
            }
            cnt[C[nodes[i]]]++;
        }
        if(bad){
            res[i]=0;
        } else {
            res[i]=1;
        }
    }
    return res;
}

Compilation message (stderr)

beechtree.cpp: In function 'std::vector<int> beechtree(int, int, std::vector<int>, std::vector<int>)':
beechtree.cpp:106:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  106 |         for(int x=1;x<nodes.size();x++){
      |                     ~^~~~~~~~~~~~~

• Subtask 0: 0 / 0
• Subtask 1: 0 / 9
• Subtask 2: 0 / 5
• Subtask 3: 0 / 9
• Subtask 4: 0 / 8
• Subtask 5: 0 / 14
• Subtask 6: 0 / 14
• Subtask 7: 0 / 12
• Subtask 8: 0 / 17
• Subtask 9: 0 / 12