Submission #515992

#	Time	Username	Problem	Language	Result	Execution time	Memory
515992		Be_dos	Marriage questions (IZhO14_marriage)	C++17	12 / 100	781 ms	262148 KiB

marriage

#include <iostream>
#include <cmath>
#include <cctype>
#include <vector>
#include <algorithm>
#include <set>
#include <map>
#include <deque>
#include <stack>
#include <unordered_set>
#include <sstream>
#include <cstring>
#include <iomanip>
#include <queue>
#include <unordered_map>
#include <random>
#include <cfloat>
#include <chrono>
#include <bitset>
#include <complex>
#include <immintrin.h>
#include <cassert>

bool try_kuhn(int32_t v, bool* vis, std::vector<int32_t>* graph, int32_t* matched, int32_t left, int32_t right) {
    vis[v] = true;
    for(int32_t i = 0; i < graph[v].size(); i++)
        if(graph[v][i] >= left && graph[v][i] <= right && matched[graph[v][i]] == -1) {
            matched[graph[v][i]] = v;
            return true;
        }
    for(int32_t i = 0; i < graph[v].size(); i++)
        if(graph[v][i] >= left && graph[v][i] <= right && try_kuhn(matched[graph[v][i]], vis, graph, matched, left, right)) {
            matched[graph[v][i]] = v;
            return true;
        }
    return false;
}

int main() {
    std::ios::sync_with_stdio(false);
    std::cin.tie(0);

    int32_t n, m, k;
    std::cin >> n >> m >> k;

    std::vector<int32_t>* graph = new std::vector<int32_t>[m];
    for(int32_t i = 0; i < k; i++) {
        int32_t src, dst;
        std::cin >> src >> dst;
        src--;
        dst--;

        graph[dst].push_back(src);
    }

    bool* vis = new bool[m];
    int32_t* matched = new int32_t[n];

    int32_t left = m - 2, right = n + 1;
    while(right - left > 1) {
        int32_t mid = (left + right) / 2;

        int32_t matched_cnt = 0;
        for(int32_t i = 0; i < n; i++)
            matched[i] = -1;
        for(int32_t i = 0; i < m; i++) {
            for(int32_t j = 0; j < m; j++)
                vis[j] = false;
            if(try_kuhn(i, vis, graph, matched, 0, mid))
                matched_cnt++;
        }
        if(matched_cnt == m)
            right = mid;
        else
            left = mid;
    }
    if(left == n) {
        std::cout << 0;
        return 0;
    }

    int32_t matched_cnt = 0;
    for(int32_t i = 0; i < n; i++)
        matched[i] = -1;
    for(int32_t i = 0; i < m; i++) {
        for(int32_t j = 0; j < m; j++)
            vis[j] = false;
        if(try_kuhn(i, vis, graph, matched, 0, right))
            matched_cnt++;
    }

    int32_t right_ptr = right;
    int32_t ans = n - right_ptr;
    for(int32_t i = 1; i < n; i++) {
        int32_t rematched = -1;
        if(matched[i - 1] != -1) {
            matched_cnt--;
            rematched = matched[i - 1];
        }

        if(rematched != -1) {
            while(right_ptr < n - 1 && matched_cnt < m) {
                right_ptr++;
                for(int32_t j = 0; j < m; j++)
                    vis[j] = false;
                if(try_kuhn(rematched, vis, graph, matched, i, right_ptr))
                    matched_cnt++;
            }
        }
        if(matched_cnt < m)
            break;

        ans += n - right_ptr;
    }
    std::cout << ans << "\n";
    return 0;
}

Compilation message (stderr)

marriage.cpp: In function 'bool try_kuhn(int32_t, bool*, std::vector<int>*, int32_t*, int32_t, int32_t)':
marriage.cpp:26:26: warning: comparison of integer expressions of different signedness: 'int32_t' {aka 'int'} and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   26 |     for(int32_t i = 0; i < graph[v].size(); i++)
      |                        ~~^~~~~~~~~~~~~~~~~
marriage.cpp:31:26: warning: comparison of integer expressions of different signedness: 'int32_t' {aka 'int'} and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   31 |     for(int32_t i = 0; i < graph[v].size(); i++)
      |                        ~~^~~~~~~~~~~~~~~~~

• Subtask 1: 12 / 100