Day 22 - Subarray Sum Equals K

Solution.kt

// https://leetcode.com/explore/featured/card/30-day-leetcoding-challenge/531/week-4/3307/

class Solution {
    fun subarraySum(nums: IntArray, k: Int): Int {
        val map = mutableMapOf<Int, Int>().withDefault { 0 }
        map[0] = 1
        var currSum = 0
        var result = 0
        
        nums.forEach {
            currSum += it
            result += map.getValue(currSum - k)
            map.put(currSum, map.getValue(currSum) + 1)
        }
        
        return result
    }
}