Submission #1153397

#	Time	Username	Problem	Language	Result	Execution time	Memory
1153397		browntoad	Rectangles (IOI19_rect)	C++20	72 / 100	5111 ms	735180 KiB

rect

#include <bits/stdc++.h>
#include "rect.h"
using namespace std;
#define ll long long
// #define int ll
#define FOR(i, a, b) for (int i = (a); i < (b); i++)
#define REP(i, n) FOR(i, 0, n)
#define RREP(i, n) for (int i = (n)-1; i >= 0; i--)
#define RREP1(i, n) for (int i = (n); i >= 1; i--)
#define REP1(i, n) FOR(i, 1, n+1)
#define pii pair<int, int>
#define ppi pair<pii, int>
#define pip pair<int, pii>
#define f first
#define s second
#define pb push_back
#define ALL(x) (x).begin(), (x).end()
#define SZ(x) (int)((x).size())
#define endl '\n'
#define IOS() ios::sync_with_stdio(false), cin.tie(0), cout.tie(0)

const ll maxn = 2505;
const ll inf = 1e9;
const ll mod = 998244353;

ll pw(ll x, ll p, ll m){
    ll ret = 1;
    while(p > 0){
        if (p & 1){
            ret *= x;
            ret %= m;
        }
        x *= x;
        x %= m;
        p >>= 1;
    }
    return ret;
}
ll inv(ll x, ll m){
    return pw(x, m-2, m);
}

int n, m;

vector<pii> rngr[maxn][maxn], rngd[maxn][maxn]; // given row, then column, the ok ranges
ll count_rectangles(vector<vector<int>> arr){
    n = SZ(arr);
    m = SZ(arr[0]);

    for (int i = 1; i <= n-2; i++){
        stack<pii> st;
        int lim = m+5;
        for (int j = m-1; j >= 0; j--){
            // subtask
            while(SZ(st)){
                if (st.top().s != j+1){
                    rngr[i][j+1].pb({j+1, st.top().s-1});
                }
                if (st.top().f > arr[i][j]) break;
                if (st.top().f == arr[i][j]) {
                    st.pop();
                    break;
                }
                st.pop();
            }

            st.push({arr[i][j], j});
        }
    }

    for (int j = 1; j <= m-2; j++){
        stack<pii> st;
        int lim = n+5;
        for (int i = n-1; i >= 0; i--){
            // subtask
            while(SZ(st)){
                if (st.top().s != i+1){
                    rngd[i+1][j].pb({i+1, st.top().s-1});

                }
                if (st.top().f > arr[i][j]) break;
                if (st.top().f == arr[i][j]) {
                    st.pop();
                    break;
                }
                st.pop();
            }

            st.push({arr[i][j], i});
        }
    }

    ll ans = 0;
    map<pii, pii> mp;
    for (int i = n-2; i >= 1; i--){
        vector<int> cnt(n);
        REP1(j, m-1){
            REP(k, n) cnt[k] = 0;

            int pre = j;
            for (auto qrng:rngr[i][j]){
                while(pre <= qrng.s){
                    for (auto mrng:rngd[i][pre]){
                        cnt[mrng.s]++;
                    }
                    pre++;
                }

                int upbd = i;
                if (mp.count(qrng) && mp[qrng].f == i+1){
                    upbd = mp[qrng].s;
                    mp[qrng].f = i;
                }
                else mp[qrng] = {i, i};

                FOR(k, i, upbd+1) ans += (cnt[k] == qrng.s-j+1);
            }
        }
    }

    return ans;
}

/*
signed main(){
    cout<<count_rectangles({{4, 8, 7, 5, 6},
{7, 4, 10, 3, 5},
{9, 7, 20, 14, 2},
{9, 14, 7, 3, 6},
{5, 7, 5, 2, 7},
{4, 5, 13, 5, 6}})<<endl;
}
*/


/*
4 4
1 2
2 3
3 1
1 4
*/

• Subtask 1: 8 / 8
• Subtask 2: 7 / 7
• Subtask 3: 12 / 12
• Subtask 4: 22 / 22
• Subtask 5: 10 / 10
• Subtask 6: 13 / 13
• Subtask 7: 0 / 28