LeetCode in Kotlin
1477. Find Two Non-overlapping Sub-arrays Each With Target Sum
Medium
You are given an array of integers arr and an integer target.
You have to find two non-overlapping sub-arrays of arr each with a sum equal target. There can be multiple answers so you have to find an answer where the sum of the lengths of the two sub-arrays is minimum.
Return the minimum sum of the lengths of the two required sub-arrays, or return -1 if you cannot find such two sub-arrays.
Example 1:
Input: arr = [3,2,2,4,3], target = 3
Output: 2
Explanation: Only two sub-arrays have sum = 3 ([3] and [3]). The sum of their lengths is 2.
Example 2:
Input: arr = [7,3,4,7], target = 7
Output: 2
Explanation: Although we have three non-overlapping sub-arrays of sum = 7 ([7], [3,4] and [7]), but we will choose the first and third sub-arrays as the sum of their lengths is 2.
Example 3:
Input: arr = [4,3,2,6,2,3,4], target = 6
Output: -1
Explanation: We have only one sub-array of sum = 6.
Constraints:
1 <= arr.length <= 1051 <= arr[i] <= 10001 <= target <= 108
Solution
class Solution {
fun minSumOfLengths(arr: IntArray, target: Int): Int {
var l = 0
var r = 0
var sum = 0
val idx = IntArray(arr.size)
idx.fill(arr.size + 1)
var ans = 2 * arr.size + 1
while (r < arr.size || sum >= target) {
if (sum < target) {
sum += arr[r]
r++
} else if (sum > target) {
sum -= arr[l]
l++
} else {
val length = r - l
idx[r - 1] = length
if (l > 0 && idx[l - 1] < arr.size + 1) {
ans = Math.min(ans, length + idx[l - 1])
}
sum -= arr[l]
l++
}
if (r > 1) {
idx[r - 1] = Math.min(idx[r - 1], idx[r - 2])
}
}
return if (ans <= 2 * arr.size) ans else -1
}
}