| # | Time | Username | Problem | Language | Result | Execution time | Memory | 
|---|---|---|---|---|---|---|---|
| 917290 | Taxiradio | 경주 (Race) (IOI11_race) | C++17 | 0 ms | 0 KiB | 
This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
#include <bits/stdc++.h>
using namespace std;
int n , k; 
vector<vector<pair<int , int>>> g;
vector<int> s;
vector<bool> removed;
vector<int> cnt;
int ans = INT_MAX;
int sz;
void get_subtree_size(int p){
    removed[p] = true;
    s[p] = 1;
    for(auto [x , y]:g[p]){
        if(!removed[x]){
            get_subtree_size(x);
            s[p] += s[x];
        }
    }
    removed[p] = false;
}
int get_centroid(int p){
    removed[p] = true;
    int centroid = p;
    for(auto [x , y]:g[p]){
        if(!removed[x] && s[x] > sz / 2){
            centroid = get_centroid(x);
            break;
        }
    }
    removed[p] = false;
    return centroid;
}
void dfs1(int p , int dis , int citys)
{
    if(k >= dis){
        ans = min(cnt[k-dis]+citys , ans);
    }else return;
    removed[p] = true;
    for(auto [x , y]:g[p]){
        if(!removed[x]){
            dfs1(x , dis+y , citys+1);
        }
    }
    removed[p] = false;
}
void dfs2(int p , int dis , int citys)
{
    if(dis <= k)cnt[dis] = min(cnt[dis] , citys);else return;
    removed[p] = true;
    for(auto [x , y]:g[p]){
        if(!removed[x]){
            dfs2(x , dis+y , citys+1);
        }
    }
    removed[p] = false;
}
void solve(int p){
    cnt[0] = 0;
    get_subtree_size(p);
    sz = s[p];
    int centroid = get_centroid(p);
    removed[centroid] = true;
    for(auto [x , y]: g[centroid]){
        if(!removed[x]){
            dfs1(x, y , 1);
            dfs2(x, y , 1);
        }
    }
    for(int i = 1; i < cnt.size(); i++){
        cnt[i] = INT_MAX-n;
    }
    for(auto [x , y]: g[centroid]){
        if(!removed[x]){
            solve(x);
        }
    }
}
int best_path(int N ,int K, int* H[2], int* L){
	n = N;
	k = K;
	g.resize(n);
	s.resize(n);
	removed.resize(n);
    cnt.resize(1000 , INT_MAX-n);
    for(int i = 0; i < n-1; i++){
        g[H[i][0]].push_back({H[i][1] , L[i]});
        g[H[i][1]].push_back({H[i][0] , L[i]});
    }
    solve(0);
	return ans;
}
