Find the smallest digit on right side of ith digit which is greater than num [ i ] up to index ' mid '
$ smallest = $ i + 1 ; $ j = 0 ; for ( $ j = $ i + 2 ; $ j <= $ mid ; $ j ++ ) if ( $ num [ $ j ] > $ num [ $ i ] && $ num [ $ j ] < $ num [ $ smallest ] ) $ smallest = $ j ;