Submission #746473

#	Time	Username	Problem	Language	Result	Execution time	Memory
746473		Sami_Massah	Race (IOI11_race)	C++17	0 / 100	9 ms	14512 KiB

race

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


const long long maxn = 2e5 + 12, mod = 998244353, inf = 1e9 + 12 ;
long long n, k, ans = maxn, h[maxn], sz[maxn], cost[maxn], U[maxn], V[maxn], dist[maxn];
int H2[maxn][2], L2[maxn];
vector <int> conn[maxn];
map <int, int> mp[maxn];
bitset <maxn> marked;
void dfs_set(int u){
    marked[u] = 1;
    sz[u] = 1;
    for(int e: conn[u]){
        int v = u ^ U[e] ^ V[e];
        if(!marked[v]){
            h[v] = h[u] + 1;
            dist[v] = dist[u] + cost[e];
            dfs_set(v);
            sz[u] += sz[v];
        }
        }
}
void dfs(int u, int p = -1){
    marked[u] = 1;
    for(int e: conn[u]){
        int v = u ^ U[e] ^ V[e];
        if(!marked[v]){
            dfs(v, u);
            if(mp[v].find(k + dist[u]) != mp[v].end())
                ans = min(ans, mp[v][k + dist[u]] - h[u]);
            }
    }
    pair<long long, int> mx = make_pair(0, -1);
    for(int e: conn[u]){
        int v = u ^ U[e] ^ V[e];
        if(v != p)
            mx = max(mx, make_pair(sz[v], v));
    }
    int f = mx.second;
    if(f != -1){
        swap(mp[f], mp[u]);
        for(int e: conn[u]){
            int v = u ^ U[e] ^ V[e];
            if(v != p && v != f){
                for(auto len: mp[v]){
                    if(mp[u].find(k + dist[u] * 2 - len.first) != mp[u].end())
                        ans = min(ans, mp[u][k + dist[u] * 2 - len.first] + len.second - 2 * h[u]);
                }
                for(auto len: mp[v]){
                    int x = mp[u][len.first];
                    if(x == 0)
                        mp[u][len.first] = len.second;
                    else
                        mp[u][len.first] = min(x, len.second);
                }


            }

        }

    }
    long long x = mp[u][dist[u]];
    if(x == 0)
        mp[u][dist[u]] = h[u];
    else
        mp[u][dist[u]] = min(x, h[u]);
}


int best_path(int N, int K, int H[][2], int L[]){
    n = N;
    k = K;
    for(int i = 0; i < n - 1; i++){
        cost[i] = L[i];
        U[i] = H[i][0];
        V[i] = H[i][1];
        conn[U[i]].push_back(i);
        conn[V[i]].push_back(i);

    }
  //  cout << n << ' ' << k << endl;
    dfs_set(1);
    marked = 0;
    dfs(1);
    return ans;
}
/*
int main(){
    int N, K;
    cin >> N >> K;
    for(int i = 0; i < N - 1; i++)
        cin >> H2[i][0] >> H2[i][0];
    for(int i = 0; i < N - 1; i++)
        cin >> L2[i];
    cout << best_path(N, K, H2, L2) << endl;

}
*/

• Subtask 1: 0 / 9
• Subtask 2: 0 / 12
• Subtask 3: 0 / 22
• Subtask 4: 0 / 57