Submission #405145

#	Time	Username	Problem	Language	Result	Execution time	Memory
405145		rocks03	Rectangles (IOI19_rect)	C++14	10 / 100	34 ms	972 KiB

rect

#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define pii pair<int, int>
#define pll pair<ll, ll>
#define ff first
#define ss second
#define pb push_back
#define SZ(x) ((int)(x).size())
#define all(x) x.begin(), x.end()
#define debug(x) cout << #x << ": " << x << " "
#define nl cout << "\n"
#define rep(i, a, b) for(int i = (a); i < (b); i++)
#define per(i, a, b) for(int i = (a); i >= (b); i--)
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

long long count_rectangles(vector<vector<int>> a){
    int N = SZ(a), M = SZ(a[0]);
    vector<int> rt[N][M], dw[N][M];
    rep(i, 0, N){
        vector<int> st;
        per(j, M - 1, 0){
            while(!st.empty() && a[i][j] > a[i][st.back()]){
                if(j + 1 < st.back()) rt[i][j].pb(st.back());
                st.pop_back();
            }
            if(!st.empty() && j + 1 < st.back()) rt[i][j].pb(st.back());
            st.pb(j);
        }
    }
    rep(j, 0, M){
        vector<int> st;
        per(i, N - 1, 0){
            while(!st.empty() && a[i][j] > a[st.back()][j]){
                if(i + 1 < st.back()) dw[i][j].pb(st.back());
                st.pop_back();
            }
            if(!st.empty() && i + 1 < st.back()) dw[i][j].pb(st.back());
            st.pb(i);
        }
    }
    auto add = [&](int i, int j, int j2){

    };
    ll ans = 0;
    rep(i, 1, N - 1){
        rep(j, 0, M){
            int curj = j + 1;
            set<int> st1;
            for(int i2 : dw[i][j]){
                st1.insert(i2);
            }
            for(int j2 : rt[i][j]){
                while(curj < j2){
                    set<int> st2;
                    for(int i2 : dw[i][curj]){
                        if(!st1.count(i2)) continue;
                        st2.insert(i2);
                    }
                    st1 = st2;
                    if(min(a[i - 1][curj], a[i + 1][curj]) > a[i][curj]) curj++;
                    else{
                        curj = -1; break;
                    }
                }
                if(curj == -1) break;
                ans += 1;
                ans += SZ(st1);
            }
        }
    }
    rep(j, 1, M - 1){
        rep(i, 0, N){
            int curi = i + 1;
            for(int i2 : dw[i][j]){
                while(curi < i2){
                    if(min(a[curi][j - 1], a[curi][j + 1]) > a[curi][j]) curi++;
                    else{
                        curi = -1; break;
                    }
                }
                if(curi == -1) break;
                if(curi - i > 2){
                    ans += 1;
                }
            }
        }
    }
    return ans;
}

Compilation message (stderr)

rect.cpp: In function 'long long int count_rectangles(std::vector<std::vector<int> >)':
rect.cpp:42:10: warning: variable 'add' set but not used [-Wunused-but-set-variable]
   42 |     auto add = [&](int i, int j, int j2){
      |          ^~~

• 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