ConstructTargetArrayWithMultipleSums1354.kt

package hard

/**
Given an array of integers target. From a starting array, A consisting of all 1's, you may perform the following procedure :

let x be the sum of all elements currently in your array.
choose index i, such that 0 <= i < target.size and set the value of A at index i to x.
You may repeat this procedure as many times as needed.
Return True if it is possible to construct the target array from A otherwise return False.



Example 1:

Input: target = [9,3,5]
Output: true
Explanation: Start with [1, 1, 1]
[1, 1, 1], sum = 3 choose index 1
[1, 3, 1], sum = 5 choose index 2
[1, 3, 5], sum = 9 choose index 0
[9, 3, 5] Done
Example 2:

Input: target = [1,1,1,2]
Output: false
Explanation: Impossible to create target array from [1,1,1,1].
Example 3:

Input: target = [8,5]
Output: true


Constraints:

N == target.length
1 <= target.length <= 5 * 10^4
1 <= target[i] <= 10^9
 */

fun isPossible(target: IntArray): Boolean {
    var total = 0
    var maxIndex=0
    target.forEachIndexed { index, num ->
        total += num
        if (target[maxIndex] > num)
            maxIndex = index
    }
        var diff =total - target[maxIndex]
        if(target[maxIndex]==1)
            return true
        if(diff >target[maxIndex])
            return false

        target[maxIndex] -= diff
        return isPossible(target)

    }