Submission #154490

#	Time	Username	Problem	Language	Result	Execution time	Memory
154490		srvlt	Marriage questions (IZhO14_marriage)	C++14	90 / 100	1570 ms	7476 KiB

marriage

//#pragma GCC optimize("Ofast")
#pragma GCC target("sse2,avx")
#include <bits/stdc++.h>
#define ll long long
#define db long double
#define pb push_back
#define pf push_front
#define ppb pop_back
#define ppf pop_front
#define fi first
#define se second
#define mp make_pair
#define endl "\n"
//#define int long long
using namespace std;

void dout() {
    cerr << endl;
}

template <typename Head, typename... Tail>
void dout(Head H, Tail... T) {
    cerr << H << ' ';
    dout(T...);
}

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

const int N = 32007;
int n, m, k, mt[N], used[N], f[N], timer;
vector <int> q[N], w[N];
bool rem[N];

bool dfs(int v) {
    if (used[v] == timer) {
        return false;
    }
    used[v] = timer;
    for (auto i : q[v]) {
        if (rem[i]) {
            continue;
        }
        if (mt[i] == -1) {
            mt[i] = v;
            f[v] = i;
            return true;
        }
    }
    for (auto i : q[v]) {
        if (rem[i]) {
            continue;
        }
        if (dfs(mt[i])) {
            mt[i] = v;
            f[v] = i;
            return true;
        }
    }
    return false;
}

bool kuhn() {
    for (int i = 0; i <= n + m; i++) {
        timer = 0;
        used[i] = 0;
        mt[i] = f[i] = -1;
    }
    for (int i = 1; i <= m; i++) {
        timer++;
        if (f[i + n] == -1) {
            dfs(i + n);
        }
    }
    for (int i = 1; i <= m; i++) {
        if (f[i + n] == -1) {
            return false;
        }
    }
    return true;
}

bool ok() {
    for (int i = 1; i <= m; i++) {
        if (f[i + n] == -1) {
            return false;
        }
    }
    return true;
}

void del2(int x) {
    rem[x] = true;
    q[x] = {};
}

void add2(int x) {
    for (auto i : w[x]) {
        q[x].pb(i);
        q[i].pb(x);
    }
}

void del(int x) {
    int tmp = mt[x];
    if (tmp != -1) {
        f[tmp] = -1;
        mt[x] = -1;
    }
    rem[x] = true;
    timer++;
    dfs(tmp);
    q[x] = {};
}

void add(int x) {
    for (auto i : w[x]) {
        q[x].pb(i);
        q[i].pb(x);
    }
    for (auto i : q[x]) {
        if (f[i] == -1) {
            timer++;
            dfs(i);
        }
    }
}

void solve2() {
    for (int i = 1; i <= k; i++) {
        int x, y;
        cin >> x >> y;
        w[x].pb(y + n);
        w[y + n].pb(x);
    }
    int j = 1, res = 0;
    for (int i = 1; i <= n; i++) {
        while (j <= n) {
            add(j);
            if (kuhn()) {
                break;
            }
            j++;
        }
        res += (n - j + 1);
        del(i);
    }
    cout << res;
}

void solve() {
    for (int i = 0; i < N; i++) {
        f[i] = mt[i] = -1;
    }
    for (int i = 1; i <= k; i++) {
        int x, y;
        cin >> x >> y;
        w[x].pb(y + n);
        w[y + n].pb(x);
    }
    int j = 1, res = 0;
    for (int i = 1; i <= n; i++) {
        while (j <= n) {
            add(j);
            if (ok()) {
                break;
            }
            j++;
        }
        res += (n - j + 1);
        del(i);
    }
    cout << res;
}

signed main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
//    freopen("input.txt", "r", stdin);
//    freopen("output.txt", "w", stdout);
    cin >> n >> m >> k;
    if (n <= 1000 && m <= 500) {
        solve2();
    }   else {
        solve();
    }
}

• Subtask 1: 90 / 100