Submission #1046143

#	Time	Username	Problem	Language	Result	Execution time	Memory
1046143		boyliguanhan	Rectangles (IOI19_rect)	C++17	100 / 100	4785 ms	928100 KiB

rect

#include "rect.h"
#include<bits/stdc++.h>
using namespace std;
#pragma GCC optimize(3)
#define all(x) x.begin(),x.end()
#define HAS(a,b) (lower_bound(all(a),b)!=upper_bound(all(a),b))
vector<int>pos[2501][2501],pos2[2501][2501],stb[2501][20];
vector<int> operator & (const vector<int>&a,const vector<int>&b){
    vector<int>c;
    if(a.size()<b.size()){
        for(auto i:a)
            if(HAS(b,i))
                c.push_back(i);
    } else for(auto i:b)
        if(HAS(a,i))
            c.push_back(i);
    return c;
}
vector<array<int,4>> ops;
int CC;
vector<int>res;
int calc(int r1,int r2,int beg){
    for(int i=20;i--;)
        if(HAS(stb[beg][i],r2))
            beg+=1<<i;
    return beg-1;
}
int cnt(int l,int r,int col){
    int x=31-__builtin_clz(r-l+1);
    vector<int>k=stb[l][x]&stb[r-(1<<x)+1][x];
    return upper_bound(k.begin(),k.end(),res[CC++])-k.begin();
}
long long count_rectangles(std::vector<std::vector<int> > a) {
    int n=a.size(),m=a[0].size();
    int ans=0;
    for(int i=1;i<n-1;i++){
        stack<int>stk;
        stk.push(m-1);
        for(int j=m-1;j--;){
            while(stk.size()&&a[i][j]>a[i][stk.top()])
                pos[i][j+1].push_back(stk.top()-1),stk.pop();
            if(stk.size()){
                pos[i][j+1].push_back(stk.top()-1);
                if(a[i][stk.top()]==a[i][j])
                    stk.pop();
            }
            stk.push(j);
            if(pos[i][j+1].size())
                pos[i][j+1].erase(pos[i][j+1].begin());
        }
    }
    for(int j=1;j<m-1;j++){
        stack<int>stk;
        stk.push(n-1);
        for(int i=n-1;i--;){
            while(stk.size()&&a[i][j]>a[stk.top()][j])
                pos2[i+1][j].push_back(stk.top()-1),stk.pop(); 
            if(stk.size()){
                pos2[i+1][j].push_back(stk.top()-1);
                if(a[stk.top()][j]==a[i][j])
                    stk.pop();
            }
            stk.push(i);
            if(pos2[i+1][j].size())
                pos2[i+1][j].erase(pos2[i+1][j].begin());
        }
    }
    for(int j=1;j<m-1;j++)
        for(int i=1;i<n-1;i++)
            for(auto x:pos2[i][j])
                ops.push_back({i,x,j,CC++});
    res.resize(CC);
    CC=0;
    sort(ops.begin(),ops.end());
    int currr=0;
    for(auto[r1,r2,col,id]:ops){
        if(r1-currr) {
            currr=r1;
            for(int i=1;i<m-1;i++)
                stb[i][0]=pos2[r1][i];
            for(int j=1;j<20;j++) for(int i=1;i+(1<<j)<m;i++)
                stb[i][j]=stb[i][j-1]&stb[i+(1<<j-1)][j-1];
        }
        res[id]=calc(r1,r2,col);
    }
    ops.clear();
    for(int col=1;col<m-1;col++){
        for(int i=1;i<n-1;i++)
            stb[i][0]=pos[i][col];
        for(int j=1;j<20;j++) for(int i=1;i+(1<<j)<n;i++)
            stb[i][j]=stb[i][j-1]&stb[i+(1<<j-1)][j-1];
        for(int row1=1;row1<n-1;row1++)
            for(auto row2:pos2[row1][col])
                ans+=cnt(row1,row2,col);
    }
    return ans;
}

Compilation message (stderr)

rect.cpp: In function 'long long int count_rectangles(std::vector<std::vector<int> >)':
rect.cpp:82:50: warning: suggest parentheses around '-' inside '<<' [-Wparentheses]
   82 |                 stb[i][j]=stb[i][j-1]&stb[i+(1<<j-1)][j-1];
      |                                                 ~^~
rect.cpp:91:46: warning: suggest parentheses around '-' inside '<<' [-Wparentheses]
   91 |             stb[i][j]=stb[i][j-1]&stb[i+(1<<j-1)][j-1];
      |                                             ~^~

• 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: 28 / 28