Find closest number in array | Returns element closest to target in arr [ ] ; Corner cases ; Doing binary search ; If target is less than array element , then search in left ; If target is greater than previous to mid , return closest of two ; Repeat for left half ; If target is greater than mid ; update i ; Only single element left after search ; Method to compare which one is the more close We find the closest by taking the difference between the target and both values . It assumes that val2 is greater than val1 and target lies between these two . ; Driver Code
function findClosest ( arr , target ) { let n = arr . length ; if ( target <= arr [ 0 ] ) return arr [ 0 ] ; if ( target >= arr [ n - 1 ] ) return arr [ n - 1 ] ; let i = 0 , j = n , mid = 0 ; while ( i < j ) { mid = ( i + j ) / 2 ; if ( arr [ mid ] == target ) return arr [ mid ] ; if ( target < arr [ mid ] ) { if ( mid > 0 && target > arr [ mid - 1 ] ) return getClosest ( arr [ mid - 1 ] , arr [ mid ] , target ) ; j = mid ; } else { if ( mid < n - 1 && target < arr [ mid + 1 ] ) return getClosest ( arr [ mid ] , arr [ mid + 1 ] , target ) ; i = mid + 1 ; } } return arr [ mid ] ; } function getClosest ( val1 , val2 , target ) { if ( target - val1 >= val2 - target ) return val2 ; else return val1 ; } let arr = [ 1 , 2 , 4 , 5 , 6 , 6 , 8 , 9 ] ; let target = 11 ; document . write ( findClosest ( arr , target ) ) ;