제출 #433942

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
433942		illyakr	경주 (Race) (IOI11_race)	C++17	0 / 100	21 ms	8996 KiB

race

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

vector<pair<int, int> > g[201010];
int sz[201010];
bool del[201010];
void rcn(int v, int pred) {
    if (del[v])return;
    sz[v] = 1;
    for (auto [to, c] : g[v]) {
        if (to == pred || del[to]) continue;
        rcn(to, v);
        sz[v] += sz[to];
    }
}
int centroid(int v, int pred, int N) {
    if (del[v])return -1;
    for (auto [to, c] : g[v]) {
        if (to == pred || del[to])continue;
        if (sz[to] > N / 2)
            return centroid(to, v, N);
    }
    return v;
}
int Kur;
int have[1010101];
int res = 1010101010;
void dfs(int v, int pred, int sum, int depth) {
    if (del[v])return;
    if (sum > Kur)return;
    if (have[Kur - sum] != -1)
        res = min(res, have[Kur - sum] + depth);
    for (auto [to, c] : g[v]) {
        if (to == pred || del[to])continue;
        dfs(to, v, sum + c, depth + 1);
    }
}
void put(int v, int pred, int sum, int depth) {
    if (del[v])return;
    if (sum > Kur)return;
    if (have[sum] != -1)
        have[sum] = min(have[sum], depth);
    else
        have[sum] = depth;
    for (auto [to, c] : g[v]) {
        if (to == pred || del[to])continue;
        dfs(to, v, sum + c, depth + 1);
    }
}

void decomposition(int v) {
    del[v] = true;
    rcn(v, v);
    for (auto [to, c] : g[v]) {
        if (del[to])continue;
        dfs(to, to, c, 1);
        put(to, to, c, 1);
    }

    for (auto [to, c] : g[v]) {
        if (del[to])continue;
        memset(have, -1, sizeof(have));
        have[0] = 0;
        decomposition(centroid(to, to, sz[to]));
    }

}

int best_path(int N, int K, int H[][2], int L[]) {
    for (int i = 0; i < N - 1; i++) {
        g[H[i][0] + 1].push_back({H[i][1] + 1, L[i]});
        g[H[i][1] + 1].push_back({H[i][0] + 1, L[i]});
    }
    memset(have, -1, sizeof(have));
    have[0] = 0;
    Kur = K;
    rcn(1, 1);
    decomposition(centroid(1, 1, N));
//    cout << centroid(1, 1, N) << " !!" << endl;

    if (res == 1010101010)return -1;
    return res;
}

/**
3 3
0 1 1
1 2 1
-1

11 12
0 1 3
0 2 4
2 3 5
3 4 4
4 5 6
0 6 3
6 7 2
6 8 5
8 9 6
8 10 7
2
*/

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