Submission #850050

#	Time	Username	Problem	Language	Result	Execution time	Memory
850050		eltu0815	Closing Time (IOI23_closing)	C++17	35 / 100	150 ms	53956 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], parent[MAX];
vector<pii> graph[MAX];

ll cost1[MAX], cost2[MAX];
ll dist1[MAX], dist2[MAX];

void init(int node, int par) {
    parent[node] = par;
    for(auto [v, w] : graph[node]) if(v != par) init(v, node);
}

void dfs(int node, int par, ll dist[]) {
    for(auto [v, w] : graph[node]) if(v != par) {
        dist[v] = dist[node] + w;
        dfs(v, node, dist);
    }
}

ll c[MAX];
vector<int> path;

int max_score(int N, int X, int Y, long long K, vector<int> U, vector<int> V, vector<int> W)
{
    path.clear();
    for(int i = 0; i < N; ++i) graph[i].clear();
    for(int i = 0; i < N; ++i) dist1[i] = dist2[i] = visited[i] = c[i] = 0;
    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]});
    }
    
    init(0, -1);
    dfs(X, -1, dist1);
    dfs(Y, -1, dist2);
    int node = X;
    while(node != -1) visited[node]++, node = parent[node];
    
    node = Y; int flag = 0;
    while(node != -1) {
        if(visited[node] == 1 && !flag) flag = 1;
        else if(flag) visited[node]--;
        else visited[node]++;
        node = parent[node];
    }
    
    node = X;
    while(node != -1 && visited[node]) {
        path.push_back(node);
        node = parent[node];
    }
    path.pop_back();
    
    vector<int> tmp;
    node = Y;
    while(node != -1 && visited[node]) {
        tmp.push_back(node);
        node = parent[node];
    }
    reverse(tmp.begin(), tmp.end());
    for(auto v : tmp) path.push_back(v);
    
    priority_queue<pair<ll, int> > pq;
    for(int i = 1; i <= 2 * N; ++i) cost1[i] = (ll)(2e18);
    int p = 0, q = path.size() - 1;
    for(int i = 1; i <= 2 * N; ++i) {
        if(p == path.size() && q == -1) break;
        if(p == path.size()) {
            cost1[i] = cost1[i - 1] + dist2[path[q]] - c[path[q]];
            c[path[q]] = dist2[path[q]]; --q;
        }
        else if(q == -1) {
            cost1[i] = cost1[i - 1] + dist1[path[p]] - c[path[p]];
            c[path[p]] = dist1[path[p]]; ++p;
        }
        else if(dist1[path[p]] - c[path[p]] <= dist2[path[q]] - c[path[q]]) {
            cost1[i] = cost1[i - 1] + dist1[path[p]] - c[path[p]];
            c[path[p]] = dist1[path[p]]; ++p;
        }
        else {
            cost1[i] = cost1[i - 1] + dist2[path[q]] - c[path[q]];
            c[path[q]] = dist2[path[q]]; --q;
        }
    }
    
    for(int i = 1; i <= 2 * N; ++i) cost2[i] = (ll)(2e18);
    for(int i = 0; i < N; ++i) if(!visited[i]) pq.push({-min(dist1[i], dist2[i]), 2 * i + 1});
    for(int i = 1; !pq.empty(); ++i) {
        ll w = -pq.top().first;
        int cur = pq.top().second;
        pq.pop();
        
        cost2[i] = min(cost2[i], cost2[i - 1] + w);
        if(cur & 1) pq.push({-(max(dist1[cur/2], dist2[cur/2]) - w), cur - 1});
    }
    
    int mx = 0;
    for(int i = 2 * N, p = 0; i >= 0; --i) {
        while(p < 2 * N && cost1[i] + cost2[p + 1] <= K) ++p;
        if(cost1[i] + cost2[p] <= K) mx = max(mx, i + p);
    }
    return mx;
}

Compilation message (stderr)

closing.cpp: In function 'int max_score(int, int, int, long long int, std::vector<int>, std::vector<int>, std::vector<int>)':
closing.cpp:75:14: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   75 |         if(p == path.size() && q == -1) break;
      |            ~~^~~~~~~~~~~~~~
closing.cpp:76:14: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   76 |         if(p == path.size()) {
      |            ~~^~~~~~~~~~~~~~

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