제출 #1170646

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1170646		anmattroi	봉쇄 시간 (IOI23_closing)	C++17	51 / 100	49 ms	17220 KiB

closing

#include "closing.h"
#include <bits/stdc++.h>
#define maxn 200005
#define fi first
#define se second
using namespace std;
using ii = pair<int, int>;

int n, x, y; int64_t k;

int64_t dp[2005][4005];
int64_t disX[2005], disY[2005];

int64_t cost_level_one[2005], cost_level_two[2005];

vector<ii> adj[2005];

void calcdisX() {

    function<void(int, int)> dfs = [&](int u, int dad) {
        for (auto [v, l] : adj[u])
        if (v != dad) {
            disX[v] = disX[u] + l;
            dfs(v, u);
        }
    };

    disX[x] = 0;
    dfs(x, -1);
}

void calcdisY() {

    function<void(int, int)> dfs = [&](int u, int dad) {
        for (auto [v, l] : adj[u])
        if (v != dad) {
            disY[v] = disY[u] + l;
            dfs(v, u);
        }
    };

    disY[y] = 0;
    dfs(y, -1);
}


int sub1() {
    vector<int64_t> nho;
    for (int i = 0; i < n; i++) nho.emplace_back(min(disX[i], disY[i]));
    sort(nho.begin(), nho.end());

    int64_t ans = 0;
    for (int i = 0; i < n; i++) {
        ans += nho[i];
        if (ans > k) return i;
    }
    return n;
}


int sub2() {
     for (int i = 0; i < n; i++) {
        cost_level_two[i] = max(disX[i], disY[i]);
        cost_level_one[i] = min(disX[i], disY[i]);
    }

    int64_t sum = 0; int cnt = 0;
    for (int i = 0; i < n; i++)
    if (disX[i] + disY[i] == disX[y]) {
        sum += cost_level_one[i];
        ++cnt;
    }

    for (int i = 0; i <= 2*n; i++) dp[n][i] = LLONG_MAX/2;

    dp[n][cnt] = sum;


    for (int i = n-1; i >= 0; i--) {
        for (int j = 0; j <= 2*n; j++) dp[i][j] = dp[i+1][j];
        if (disX[i] + disY[i] == disX[y]) {
            for (int j = 0; j <= 2*n; j++)
                if (j+1 <= 2*n) dp[i][j+1] = min(dp[i][j+1], dp[i+1][j] + cost_level_two[i] - cost_level_one[i]);
            continue;
        }

        for (int j = 0; j <= 2*n; j++) {
            if (j+1 <= 2*n) dp[i][j+1] = min(dp[i][j+1], dp[i+1][j] + cost_level_one[i]);
            if (j+2 <= 2*n) dp[i][j+2] = min(dp[i][j+2], dp[i+1][j] + cost_level_two[i]);
        }
    }

    int ans = 0;
    for (int i = 0; i <= 2*n; i++) if (dp[0][i] <= k) ans = i;
    return ans;
}

int max_score(int N, int X, int Y, long long K, vector<int> U, vector<int> V, vector<int> W) {
    n = N; x = X; y = Y; k = K;
    for (int i = 0; i < N-1; i++) {
        adj[U[i]].emplace_back(V[i], W[i]);
        adj[V[i]].emplace_back(U[i], W[i]);
    }
    calcdisX(); calcdisY();
    int ans = max(sub1(), sub2());
    for (int i = 0; i < N; i++) adj[i].clear();
    for (int i = 0; i <= N; i++) for (int j = 0; j <= 2*N; j++) dp[i][j] = 0;
    return ans;
}
/*
2
7 0 2 10
0 1 2
0 3 3
1 2 4
2 4 2
2 5 5
5 6 3
4 0 3 20
0 1 18
1 2 1
2 3 19
*/
/*
1
4 0 3 20
0 1 18
1 2 1
2 3 19
*/

• Subtask 0: 0 / 0
• Subtask 1: 0 / 8
• Subtask 2: 9 / 9
• Subtask 3: 12 / 12
• Subtask 4: 0 / 14
• Subtask 5: 9 / 9
• Subtask 6: 11 / 11
• Subtask 7: 10 / 10
• Subtask 8: 0 / 10
• Subtask 9: 0 / 17