Submission #848710

#	Time	Username	Problem	Language	Result	Execution time	Memory
848710		math_rabbit_1028	Closing Time (IOI23_closing)	C++17	83 / 100	1049 ms	44260 KiB

closing

#include "closing.h"
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<ll, ll> pll;
 
int n, x, y, ch[202020], ans;
ll k, need[202020], dis[202020];
vector< pair<int, ll> > adj[202020];
priority_queue<pll> pq;
 
int L, midp;
vector< pair<int, ll> > path;
void find_path(int v) {
    for (int i = 0; i < adj[v].size(); i++) {
        if (path.back().first == y) return;
        int u = adj[v][i].first; ll w = adj[v][i].second;
        if (ch[u] == 1) continue;
        ch[u] = 1;
        path.push_back({u, w});
        find_path(u);
        if (path.back().first != y) path.pop_back();
    }
}

int not_intersect() {
    int cnt = 0;
    for (int i = 0; i < n; i++) ch[i] = 0;
    while (!pq.empty()) pq.pop();

    pq.push({-0, x});
    pq.push({-0, y});
 
    while (!pq.empty()) {
        int v = pq.top().second; ll w = -pq.top().first;
        pq.pop();
        if (k - w >= 0) {
            cnt++;
            k -= w;
        }
        else break;
 
        ch[v] = 1;
        for (int i = 0; i < (int)adj[v].size(); i++) {
            if (ch[adj[v][i].first] == 1) continue;
            if (v == path[midp - 1].first && adj[v][i].first == path[midp].first) continue; 
            if (v == path[midp].first && adj[v][i].first == path[midp - 1].first) continue; 
            pq.push({-w-adj[v][i].second, adj[v][i].first});
        }
    }

    return cnt;
}
 
ll dp[404040], nxt[404040];
void update(ll a, ll b) {
    for (int i = 0; i <= 2*n; i++) {
        ll val = dp[i];
        if (i >= 1) val = min(val, dp[i - 1] + a);
        if (i >= 2) val = min(val, dp[i - 2] + b);
        nxt[i] = val;
    }
    for (int i = 0; i <= 2*n; i++) dp[i] = nxt[i];
}
void DFS(int v, ll a, ll b) {
    for (int i = 0; i < adj[v].size(); i++) {
        int u = adj[v][i].first; ll w = adj[v][i].second;
        if (ch[u] == 1) continue;
        ch[u] = 1;
        update(a + w, b + w);
        DFS(u, a + w, b + w);
    }
}

int intersect() {
    for (int i = 0; i < n; i++) ch[i] = 0;
    for (int i = 0; i <= L; i++) ch[path[i].first] = 1;
    for (int i = 0; i <= 2*n; i++) dp[i] = 2e18;
    dp[0] = 0;

    for (int i = 0; i < midp; i++) need[i] = dis[i] - dis[0];
    for (int i = midp; i <= L; i++) need[i] = dis[L] - dis[i];
    for (int i = 1; i <= L; i++) k -= need[i];

    if (k < 0) return 0;

    for (int i = 0; i < midp; i++) {
        assert(dis[L] - dis[i] - need[i] >= 0);
        update(dis[L] - dis[i] - need[i], 2e18);
        ll a = dis[i] - dis[0];
        ll b = dis[L] - dis[i];
        assert(a <= b);
        DFS(path[i].first, a, b);
    }
    for (int i = midp; i <= L; i++) {
        assert(dis[i] - dis[0] - need[i] >= 0);
        update(dis[i] - dis[0] - need[i], 2e18);
        ll a = dis[L] - dis[i];
        ll b = dis[i] - dis[0];
        assert(a <= b);
        DFS(path[i].first, a, b);
    }

    int out = upper_bound(dp, dp + 2*n + 1, k) - dp - 1;
    return L + out + 1;
}
 
int max_score(int N, int X, int Y, ll K, vector<int> U, vector<int> V, vector<int> W) {
    n = N, x = X, y = Y, k = K;
 
    ans = 0;
    for (int i = 0; i < n; i++) adj[i].clear();
    path.clear();
 
    for (int i = 0; i < (int)U.size(); i++) {
        adj[U[i]].push_back({V[i], W[i]});
        adj[V[i]].push_back({U[i], W[i]});
    }
 
    for (int i = 0; i < n; i++) ch[i] = 0;
    path.push_back({x, 0});
    ch[x] = 1;
    find_path(x);
    assert(path.back().first == y);
    L = path.size() - 1;

    for (int i = 1; i <= L; i++) dis[i] = dis[i - 1] + path[i].second;
    
    for (int i = 0; i <= L; i++) {
        if (dis[i] - dis[0] > dis[L] - dis[i]) {
            midp = i;
            break;
        }
    }

    k = K;
    ans = not_intersect();
    
    k = K;
    ans = max(ans, intersect());
 
    return ans;
}

Compilation message (stderr)

closing.cpp: In function 'void find_path(int)':
closing.cpp:15:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   15 |     for (int i = 0; i < adj[v].size(); i++) {
      |                     ~~^~~~~~~~~~~~~~~
closing.cpp: In function 'void DFS(int, ll, ll)':
closing.cpp:66:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   66 |     for (int i = 0; i < adj[v].size(); i++) {
      |                     ~~^~~~~~~~~~~~~~~

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