Swaps 1 with 0 in the string str1
if ( str1 [ i ] == '1' && str2 [ i ] == '0' ) { StringBuilder sb = new StringBuilder ( str1 ) ; sb [ i ] = '0' ; str1 = sb . ToString ( ) ; curStr1Ones ++ ; } } } if ( flag == 0 ) { Console . WriteLine ( " Possible " ) ; }