Maximum size square sub-matrix with all 1s
動畫
#include <bits/stdc++.h>
#define m 5
#define n 5
using namespace std;
int main(){
ios::sync_with_stdio(0), cin.tie(0);
int a[m][n] = {{0,1,1,0,1},
{1,1,1,1,0},
{0,1,1,1,0},
{1,1,1,1,0},
{0,0,0,0,0}};
int a2[m][n];
for(int i=0; i<m; i++)
a2[i][0] = a[i][0];
for(int j=0; j<n; j++)
a2[0][j] = a[0][j];
for(int i=1; i<m; i++){
for(int j=1; j<n; j++){
if(a[i][j] == 1)
a2[i][j] = min(a[i-1][j],min(a[i][j-1],a[i-1][j-1])) + 1;
else
a2[i][j] = 0;
}
}
int max_a2 = a2[0][0], max_i = 0, max_j = 0;
for(int i=0; i<m; i++){
for(int j=0; j<n; j++){
if(a2[i][j] >= max_a2){
max_a2 = a2[i][j];
max_i = i;
max_j = j;
}
}
}
//a
for(int i=0; i<m; i++){
for(int j=0; j<n; j++)
cout << a[i][j] << ' ';
cout << '\n';
}
cout << '\n';
//a2
for(int i=0; i<m; i++){
for(int j=0; j<n; j++)
cout << a2[i][j] << ' ';
cout << '\n';
}
cout << '\n';
//Maximum sub-matrix
for(int i=max_i; i >= max_i-max_a2; i--){
for(int j=max_j; j >= max_j-max_a2; j--)
cout << a[i][j] << ' ';
cout << '\n';
}
}
0 1 1 0 1
1 1 1 1 0
0 1 1 1 0
1 1 1 1 0
0 0 0 0 0
0 1 1 0 1
1 1 2 1 0
0 1 2 2 0
1 1 2 2 0
0 0 0 0 0
1 1 1
1 1 1
1 1 1