| # | Time | Username | Problem | Language | Result | Execution time | Memory |
|---|---|---|---|---|---|---|---|
| 1045611 | vjudge1 | Rectangles (IOI19_rect) | C++17 | 0 ms | 0 KiB |
This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
#include "rect.h"
#include<bits/stdc++.h>
using namespace std;
bitset<2501>pos[2501][2501];
set<int>pos2[2501][2501];
bitset<2501>stb[2501][20];
int cnt(int l,int r){
int x=31-__builtin_clz(r-l+1);
return (stb[l][x]&stb[r-(1<<x)+1][x]).count();
}
long long count_rectangles(std::vector<std::vector<int> > a) {
int n=a.size(),m=a[0].size();
long long 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][stk.top()-1]=1,stk.pop();
if(stk.size()){
pos[i][j+1][stk.top()-1]=1;
if(a[i][stk.top()]==a[i][j])
stk.pop();
}
stk.push(j);
pos[i][j+1][j]=0;
}
}
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].insert(stk.top()-1),stk.pop();
if(stk.size()){
pos2[i+1][j].insert(stk.top()-1);
if(a[stk.top()][j]==a[i][j])
stk.pop();
}
stk.push(i);
pos2[i+1][j].erase(i);
}
}
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);
}
return ans;
}