Submission #446435

#	Time	Username	Problem	Language	Result	Execution time	Memory
446435		SirCovidThe19th	Race (IOI11_race)	C++14	100 / 100	514 ms	87956 KiB

race

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

#define f first
#define s second

int K, ans = INT_MAX; vector<pair<int, int>> adj[200005]; set<pair<int, int>> S[200005];

void dfs(int i, int p, int dis, int dep){
    S[i].insert({dis, dep});
    for (auto nxt : adj[i]) if (nxt.f != p){
        dfs(nxt.f, i, dis+nxt.s, dep+1);
        if (S[i].size() < S[nxt.f].size()) swap(S[i], S[nxt.f]);
        for (auto d : S[nxt.f]){
            int other = K+2*dis-d.f; auto x = S[i].lower_bound({other, -1});
            if (x != S[i].end() and (*x).f == other) ans = min(ans, d.s+(*x).s-2*dep);
        }for (auto d : S[nxt.f]) S[i].insert(d);
    }
}
int best_path(int n, int k, int h[][2], int l[]){
    for (int i = 0; i < n-1; i++){
        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(0, 0, 0, 0); return (ans == INT_MAX) ? -1 : ans;
}

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