Submission #1063632

#	Time	Username	Problem	Language	Result	Execution time	Memory
1063632		kkkkkkkk	Race (IOI11_race)	C++17	0 / 100	2 ms	12888 KiB

race

#include <bits/stdc++.h>

using namespace std;

vector<pair<int,int> > G[200005];
bool is_removed[200005];
int subtree_size[200005];
int rez=INT_MAX;
int cekori[1000005];
int k;

int get_subtree_size(int teme, int parent=-1) {
    subtree_size[teme]=1;
    for (auto [next, dolz]:G[teme]) {
        if (next==parent||is_removed[next]) continue;
        subtree_size[teme]+=get_subtree_size(next, teme);
    }
    return subtree_size[teme];
}

int get_centroid(int teme, int tree_size, int parent=-1) {
    for (auto [next, dolz]:G[teme]) {
        if (next==parent||is_removed[next]) continue;
        if (subtree_size[next]*2>tree_size)
            return get_centroid(next, tree_size, teme);
    }
    return teme;
}

queue<int> q;

void dfs2(int teme, int parent=-1, int dolz=0, int depth=0) {
    if (dolz>=k) {
        if (dolz==k) rez=min(rez, depth);
        return;
    }
    if (cekori[dolz]>depth) cekori[dolz]=depth;
    else if (cekori[dolz]==-1) cekori[dolz]=depth, q.push(dolz);
    if (cekori[k-dolz]!=-1)
        rez=min(rez, cekori[k-dolz]+depth);
    for (auto [next, dist]:G[teme]) {
        if (next==parent||is_removed[next]) continue;
        dfs2(next, teme, dolz+dist, depth+1);
    }
}

void build_centroid_decomp(int teme=0) {
    int centroid=get_centroid(teme, get_subtree_size(teme));
    dfs2(centroid);
    while (!q.empty()) {
        int br=q.front();
        q.pop();
        cekori[br]=-1;
    }
    is_removed[centroid]=1;
    for (auto [next, dist]:G[centroid]) {
        if (is_removed[next]) continue;
        build_centroid_decomp(next);
    }
}

int best_path(int n, int K, int H[][2], int L[]) {
    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]});
    }
    k=K;
    memset(cekori, -1, sizeof(cekori));
    build_centroid_decomp();
    if (rez==INT_MAX) return -1;
    return rez;
}

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