Submission #848656

#	Time	Username	Problem	Language	Result	Execution time	Memory
848656		eltu0815	Closing Time (IOI23_closing)	C++17	21 / 100	1051 ms	25820 KiB

closing

#include "closing.h"

#include <bits/stdc++.h>
#define MAX 200005
using namespace std;

typedef long long ll;
typedef pair<int, int> pii;

int visited[MAX];
vector<pii> graph[MAX];
ll dist1[MAX], dist2[MAX];

void dfs1(int node) {
    visited[node] = 1;
    for(auto [v, w] : graph[node]) {
        if(visited[v]) continue;
        dist1[v] = dist1[node] + w;
        dfs1(v);
    }
}

void dfs2(int node) {
    visited[node] = 1;
    for(auto [v, w] : graph[node]) {
        if(visited[v]) continue;
        dist2[v] = dist2[node] + w;
        dfs2(v);
    }
}

ll c[MAX];

int max_score(int N, int X, int Y, long long K, vector<int> U, vector<int> V, vector<int> W)
{
    for(int i = 0; i < N; ++i) graph[i].clear();
    for(int i = 0; i < N - 1; ++i) {
        graph[U[i]].push_back({V[i], W[i]});
        graph[V[i]].push_back({U[i], W[i]});
    }
    
    for(int i = 0; i < N; ++i) visited[i] = dist1[i] = 0;
    dfs1(X);
    
    for(int i = 0; i < N; ++i) visited[i] = dist2[i] = 0;
    dfs2(Y);
    
    int ans = 0;
    for(int p = X; p < N; ++p) for(int q = 0; q <= Y; ++q) {
        for(int i = 0; i < N; ++i) c[i] = 0;
        for(int i = X; i <= p; ++i) c[i] = max(c[i], dist1[i]);
        for(int i = q; i <= Y; ++i) c[i] = max(c[i], dist2[i]);
        
        ll sum = 0;
        int cur = p - X + Y - q + 2;
        for(int i = 0; i < N; ++i) sum += c[i];
        
        if(sum > K) continue;
        
        int a = X, b = Y;
        while(true) {
            if(a == 0 && b == N - 1) break;
            if(a == 0) {
                ll val = max(0ll, dist2[b + 1] - c[b + 1]);
                if(sum + val <= K) sum += val, ++cur, ++b;
                else break;
                continue;
            }
            if(b == N - 1) {
                ll val = max(0ll, dist1[a - 1] - c[a - 1]);
                if(sum + val <= K) sum += val, ++cur, --a;
                else break;
                continue;
            }
            ll val1 = max(0ll, dist1[a - 1] - c[a - 1]);
            ll val2 = max(0ll, dist2[b + 1] - c[b + 1]);
            if(val1 <= val2) {
                if(sum + val1 <= K) sum += val1, ++cur, --a;
                else break;
            }
            else {
                if(sum + val2 <= K) sum += val2, ++cur, ++b;
                else break;
            }
        }
        
        ans = max(ans, cur);
    }
    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
*/

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