Sum of Unique Elements (LeetCode 1748) | Full solution with a frequency array

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Actual problem on LeetCode: leetcode.com/problems/sum-of-...
Chapters:
00:00 - Intro
00:40 - Problem Statement
02:23 - Brute Force Method
04:01 - Frequency Array
08:21 - Dry-run of Code
10:26 - Final Thoughts
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Пікірлер: 10

@spandansahu Ай бұрын

class Solution { public int sumOfUnique(int[] nums) { Map map = new HashMap(); int sum = 0; for (int i = 0; i < nums.length; i++) { if (map.containsKey(nums[i])) { map.put(nums[i], map.get(nums[i]) + 1); } else { map.put(nums[i], 1); } } for (int key : map.keySet()) { if (map.get(key) == 1) { sum += key; } } return sum; } }

@SubhajitDas-mt7sn Ай бұрын

for cpp : class Solution { public: int sumOfUnique(vector& nums) { unordered_mapmp; for(int i:nums) mp[i]++; int sum=0; for(auto it:mp){ if(it.second==1) sum+=it.first; } return sum; } };

@udayrajvadeghar8555 Ай бұрын

amazing explanation sir!!

@Vikashkumarsinha007 Ай бұрын

H index please sir

@giftbanda9795 Ай бұрын

I see you have 'int[] freq = new int[101]" what happens when you have an array with 200 elements?

@s260888 Ай бұрын

The condition is, it will be less than 101

@nikoo28 Ай бұрын

the problem constraints limit to 100. If you have 200, then the array will have a length of 200

@giftbanda9795 Ай бұрын

/** * Calculates the sum of unique elements in an array. * Time Complexity: O(n) where n is the length of the array. * Space Complexity: O(n) for storing the elements in the HashMap. */ public static int sumOfUniqueElements(int[] arr) { if (arr.length < 1) return 0; Map map = new HashMap(); int sum = 0; for (int key : arr) { map.put(key, map.getOrDefault(key, 0) + 1); } for (int key : map.keySet()) { if (map.get(key) == 1) { sum += key; } } return sum; }

@code2compass Ай бұрын

In python you can do: return sum(set(arr)) One more thing! Using an array is a good approach but it may not work for all tests because: Arr = [16, 20, 2] For i in range(len(arr)): Arr[i]

@s260888 Ай бұрын

@Nikhil Lohia, great work! I’m a big fan of yours. I have a better version of it; please check it out. public int sumOfUnique(int[] nums) { int[] set = new int[101]; int count =0; for(int i=0; i