to extract last digit divide by p then % 10 Store count of occurrences in cnt [ ]
int cnt [ 10 ] = { 0 } ; for ( int i = 0 ; i < n ; i ++ ) { cnt [ ( arr [ i ] [ q ] / p ) % 10 ] ++ ; } for ( int i = 1 ; i < 10 ; i ++ ) { cnt [ i ] += cnt [ i - 1 ] ; } int ans [ n ] [ 3 ] ; for ( int i = n - 1 ; i >= 0 ; i -- ) { int lastDigit = ( arr [ i ] [ q ] / p ) % 10 ;