Given a binary matrix, find out the maximum size square sub-matrix with all 1s.
For example, consider the below binary matrix.0 1 1 0 1 1 1 0 1 0 0 1 1 1 0 1 1 1 1 0 1 1 1 1 1 0 0 0 0 0The maximum square sub-matrix with all set bits is
1 1 1 1 1 1 1 1 1
http://www.geeksforgeeks.org/maximum-size-sub-matrix-with-all-1s-in-a-binary-matrix/
Method 1:Dynamic Programming
#include<stdio.h> #define bool int #define R 6 #define C 5 int min(int a, int b, int c) { int m = a; if (m > b) m = b; if (m > c) m = c; return m; } void printMaxSubSquare(bool M[R][C]) { int i,j; int S[R][C]; int max_of_s, max_i, max_j; for(i = 0; i < R; i++) S[i][0] = M[i][0]; for(j = 0; j < C; j++) S[0][j] = M[0][j]; for(i = 1; i < R; i++) { for(j = 1; j < C; j++) { if(M[i][j] == 1) S[i][j] = min(S[i][j-1], S[i-1][j], S[i-1][j-1]) + 1; else S[i][j] = 0; } } max_of_s = S[0][0]; max_i = 0; max_j = 0; for(i = 0; i < R; i++) { for(j = 0; j < C; j++) { if(max_of_s < S[i][j]) { max_of_s = S[i][j]; max_i = i; max_j = j; } } } printf("\nMaximum size sub-matrix is: \n"); for(i = max_i; i > max_i - max_of_s; i--) { for(j = max_j; j > max_j - max_of_s; j--) { printf("%d ", M[i][j]); } printf("\n"); } } int main() { bool M[R][C] = {{0, 1, 1, 0, 1}, {1, 1, 0, 1, 0}, {0, 1, 1, 1, 0}, {1, 1, 1, 1, 0}, {1, 1, 1, 1, 1}, {0, 0, 0, 0, 0}}; printMaxSubSquare(M); getchar(); }
Time Complexity: O(m*n) where m is number of rows and n is number of columns in
the given matrix.
Auxiliary Space: O(m*n) where m is number of rows and n is number of columns in
the given matrix.
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