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| 1 | +/** |
| 2 | + * @param {number[]} nums Array of integers. |
| 3 | + * @param {number} target Sum target of subarray elements. |
| 4 | + * @return {boolean} True if subarray of at least length 2 exists which elements add up to target |
| 5 | + * @summary Two Sum {@link https://leetcode.com/problems/continuous-subarray-sum/} |
| 6 | + * @description Given an array of integers, return indices of the two numbers such that they add up to a specific target. |
| 7 | + * Space O(t) - dictionary with at most size of target entries. |
| 8 | + * Time O(n) - we iterate through nums array once. |
| 9 | + */ |
| 10 | +const checkSubarraySum = (nums, target) => { |
| 11 | + const lookup = { 0: -1 }; |
| 12 | + let movingModulo = 0; |
| 13 | + |
| 14 | + for (let index = 0; index < nums.length; index++) { |
| 15 | + movingModulo += nums[index]; |
| 16 | + if (target !== 0) movingModulo = movingModulo % target; |
| 17 | + |
| 18 | + if (lookup[movingModulo] !== undefined) { |
| 19 | + if (index - lookup[movingModulo] >= 2) return true; |
| 20 | + } else lookup[movingModulo] = index; |
| 21 | + } |
| 22 | + |
| 23 | + return false; |
| 24 | +}; |
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