Minimum cells to be flipped to get a 2 * 2 submatrix with equal elements | Java implementation of the approach ; Function to return the minimum flips required such that the submatrix from mat [ i ] [ j ] to mat [ i + 1 ] [ j + 1 ] contains all equal elements ; Function to return the minimum number of slips required such that the matrix contains at least a single submatrix of size 2 * 2 with all equal elements ; To store the result ; For every submatrix of size 2 * 2 ; Update the count of flips required for the current submatrix ; Driver code
class GFG { static int minFlipsSub ( String mat [ ] , int i , int j ) { int cnt0 = 0 , cnt1 = 0 ; if ( mat [ i ] . charAt ( j ) == '1' ) cnt1 ++ ; else cnt0 ++ ; if ( mat [ i ] . charAt ( j + 1 ) == '1' ) cnt1 ++ ; else cnt0 ++ ; if ( mat [ i + 1 ] . charAt ( j ) == '1' ) cnt1 ++ ; else cnt0 ++ ; if ( mat [ i + 1 ] . charAt ( j + 1 ) == '1' ) cnt1 ++ ; else cnt0 ++ ; return Math . min ( cnt0 , cnt1 ) ; } static int minFlips ( String mat [ ] , int r , int c ) { int res = Integer . MAX_VALUE ; for ( int i = 0 ; i < r - 1 ; i ++ ) { for ( int j = 0 ; j < c - 1 ; j ++ ) { res = Math . min ( res , minFlipsSub ( mat , i , j ) ) ; } } return res ; } public static void main ( String [ ] args ) { String mat [ ] = { "0101" , "0101" , "0101" } ; int r = mat . length ; int c = mat [ 0 ] . length ( ) ; System . out . print ( minFlips ( mat , r , c ) ) ; } }