Find the subarray of size m such that difference between last ( maximum in case of sorted ) and first ( minimum in case of sorted ) elements of subarray is minimum .
for ( int i = 0 ; i + m - 1 < n ; i ++ ) { int diff = arr [ i + m - 1 ] - arr [ i ] ; if ( diff < min_diff ) min_diff = diff ; } return min_diff ; }