제출 #671649

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
671649		shrimb	경주 (Race) (IOI11_race)	C++17	100 / 100	435 ms	101232 KiB

race

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

vector<pair<int,int>>adj[200001];
int dsu[200001],sz[200001];
map<long long,int> store[200001];
long long sum[200001];
long long ans = INT_MAX, K;

int Find(int x){
    return x == dsu[x] ? x : dsu[x] = Find(dsu[x]);
}

void Unite(int a, int b, long long cur_k, int cur_depth){
    a = Find(a); b = Find(b);
    if(sz[a] > sz[b]) swap(a,b);
    sz[b] += sz[a];
    dsu[a] = b;
    for(auto &s: store[a]){
        if(store[b].count(cur_k - s.first)){
            ans = min(ans, (long long)s.second - cur_depth + store[b][cur_k - s.first] - cur_depth);
        }
    }
    for(auto &s: store[a]){
        if(!store[b].count(s.first) or store[b][s.first] > s.second){
            store[b][s.first] = s.second;
        }
    }
}
void dfs(int x, int par, int depth){
    for(auto s: adj[x]){
        if(s.first != par){
            sum[s.first] = s.second + sum[x];
            dfs(s.first, x, depth + 1);
        }
    }
    store[x][sum[x]] = depth;
    for(auto s: adj[x]){
        if(s.first != par){
            Unite(x, s.first, 2ll * sum[x] + K, depth);
        }
    }
    // int b = Find(x);
    // if(store[b].count(sum[x] + K) != 0) ans = min(ans, (long long)store[b][sum[x] + K]  - depth);
}
signed best_path(signed n, signed k, signed h[][2], signed l[]){
    for (int i = 1 ; i <= n ; i++) sz[i] = 1, dsu[i] = i;
    ans = INT_MAX;
    for(int i = 0; i < n - 1; i++){
        h[i][0]++; h[i][1]++;
        adj[h[i][0]].push_back({h[i][1], l[i]});
        adj[h[i][1]].push_back({h[i][0], l[i]});
    }
    K = k;
    dfs(1, 0, 1);

    if(ans == INT_MAX) ans = -1;
  return ans;
}

• Subtask 1: 9 / 9
• Subtask 2: 12 / 12
• Subtask 3: 22 / 22
• Subtask 4: 57 / 57