Submission #161810

#	Time	Username	Problem	Language	Result	Execution time	Memory
161810		andrew	Rectangles (IOI19_rect)	C++17	10 / 100	11 ms	888 KiB

rect

#include <bits/stdc++.h>
#include "rect.h"

#define fi first
#define se second
#define pll pair<ll, ll>
#define pii pair<int, int>


using namespace std;
typedef long long ll;
typedef long double ld;
const ll MAXN = 1123456;
const ll N = 2510, M = 90;

int prv[N][N], nxt[N][N];
int prv1[N][N], nxt1[N][N];

deque <pii> q;

int strU[M][M][M], strD[M][M][M], stlL[M][M][M], stlR[M][M][M];

long long count_rectangles(vector<vector<int> > a) {
    ll n = a.size(), m = a[0].size();
    if(n < 3)return 0;
    if(n == 3){
        int ans = 0, mx = 0;
        for(int i = 1; i < m - 1; i++){
            mx = 0;
            for(int j = i; j < m - 1; j++){
                mx = max(mx, a[1][j]);
                if(a[0][j] <= a[1][j] || a[2][j] <= a[1][j])break;
                if(a[1][i - 1] > mx && mx < a[1][j + 1])ans++;
            }
        }
        return ans;
    }

    for(int i = 0; i < n; i++){
        vector <pii> st;
        st.push_back({1e8, -1});

        for(int j = 0; j < m; j++){
            while(!st.empty() && st.back().fi <= a[i][j])st.pop_back();
            prv[i][j] = st.back().se;
            st.push_back({a[i][j], j});
        }

        st.clear();
        st.push_back({1e8, m});

        for(int j = m - 1; j >= 0; j--){
            while(!st.empty() && st.back().fi <= a[i][j])st.pop_back();
            nxt[i][j] = st.back().se;
            st.push_back({a[i][j], j});
        }
        st.clear();
    }


    for(int j = 0; j < m; j++){
        vector <pii> st;
        st.push_back({1e8, -1});

        for(int i = 0; i < n; i++){
            while(!st.empty() && st.back().fi <= a[i][j])st.pop_back();
            prv1[i][j] = st.back().se;
            st.push_back({a[i][j], i});
        }

        st.clear();
        st.push_back({1e8, n});

        for(int i = n - 1; i >= 0; i--){
            while(!st.empty() && st.back().fi <= a[i][j])st.pop_back();
            nxt1[i][j] = st.back().se;
            st.push_back({a[i][j], i});
        }
        st.clear();
    }

//    for(int i = 0; i < n; i++){
//        for(int l = 0; l < m; l++){
//
//        }
//    }

    int ans = 0;

    for(int r1 = 1; r1 < n - 1; r1++)
        for(int c1 = 1; c1 < m - 1; c1++)
        for(int r2 = r1; r2 < n - 1; r2++)
        for(int c2 = c1; c2 < m - 1; c2++){
            bool ok = 1;
            for(int i = c1; i <= c2; i++){
                if(nxt1[r1 - 1][i] <= r2)ok = 0;
            }
            for(int i = c1; i <= c2; i++){
                if(prv1[r2 + 1][i] >= r1)ok = 0;
            }
            for(int i = r1; i <= r2; i++){
                if(nxt[i][c1 - 1] <= c2)ok = 0;
            }
            for(int i = r1; i <= r2; i++){
                if(prv[i][c2 + 1] >= c1)ok = 0;
            }
            ans += ok;
        }

	return ans;
}

Compilation message (stderr)

rect.cpp: In function 'long long int count_rectangles(std::vector<std::vector<int> >)':
rect.cpp:90:5: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
     for(int r1 = 1; r1 < n - 1; r1++)
     ^~~
rect.cpp:110:2: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'for'
  return ans;
  ^~~~~~

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