Function to perform binary search on an array sorted in increasing order l and r represent the left and right index of the row to be searched
function binarySearchRowInc ( $ arr , $ row , $ l , $ r , $ x ) { while ( $ l <= $ r ) { $ mid = ( int ) ( ( $ l + $ r ) / 2 ) ; if ( $ arr [ $ row ] [ $ mid ] == $ x ) return $ mid ; if ( $ arr [ $ row ] [ $ mid ] < $ x ) $ l = $ mid + 1 ; else $ r = $ mid - 1 ; } return -1 ; }