Description
Find Two Non-overlapping Sub-arrays Each With Target Sum
MediumYou 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
Solutions
Sliding window + shenanigans.
Language: javascript()DONE
CPU Performance57.53%
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Memory Performance91.97%
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/** By Leetcode */
var minSumOfLengths = function (arr, target) {
const n = arr.length;
const dp = Array(n + 1).fill(n);
let res = n + 1;
let sum = 0;
let left = 0;
for (let right = 0; right < n; right++) {
sum += arr[right];
while (sum > target) {
sum -= arr[left];
left++;
}
dp[right + 1] = dp[right];
if (sum === target) {
const length = right - left + 1;
res = Math.min(res, length + dp[left]);
dp[right + 1] = Math.min(dp[right], length);
}
}
return res === n + 1 ? -1 : res;
};