1185-find-in-mountain-array.kt

classSolution {
privatefun MountainArray.findTarget(left:Int, right:Int, target:Int, isUpside:Boolean): Int {
 @Suppress("NAME_SHADOWING") var left = left
 @Suppress("NAME_SHADOWING") var right = right
while (left <= right) {
val mid = (left + right) /2
val midValue = get(mid)
if (midValue == target) {
return mid
 }
if (isUpside) {
if (target > midValue) {
 left = mid +1
 } else {
 right = mid -1
 }
 } else {
if (target > midValue) {
 right = mid -1
 } else {
 left = mid +1
 }
 }
 }
return-1
 }

privatefun MountainArray.findPeak(): Int {
var left =0
var right = length() -1
while (left < right) {
val mid = (left + right) /2
if (get(mid) < get(mid +1)) {
 left = mid +1
 } else {
 right = mid
 }
 }
return left
 }

funfindInMountainArray(target:Int, mountainArr:MountainArray): Int {
val peak = mountainArr.findPeak()

val leftsideResult = mountainArr.findTarget(0, peak, target, true)
if (leftsideResult !=-1)
return leftsideResult

return mountainArr.findTarget(peak, mountainArr.length() -1, target, false)
 }
}