Welcome to Subscribe On Youtube

Formatted question description: https://leetcode.ca/all/2363.html

2363. Merge Similar Items

  • Difficulty: Easy.
  • Related Topics: Array, Hash Table, Sorting, Ordered Set.
  • Similar Questions: .

Problem

You are given two 2D integer arrays, items1 and items2, representing two sets of items. Each array items has the following properties:

  • items[i] = [valuei, weighti] where valuei represents the value and weighti represents the **weight **of the ith item.

  • The value of each item in items is unique.

Return a 2D integer array ret where ret[i] = [valuei, weighti], with weighti being the **sum of weights of all items with value** valuei.

Note: ret should be returned in ascending order by value.

  Example 1:

Input: items1 = [[1,1],[4,5],[3,8]], items2 = [[3,1],[1,5]]
Output: [[1,6],[3,9],[4,5]]
Explanation: 
The item with value = 1 occurs in items1 with weight = 1 and in items2 with weight = 5, total weight = 1 + 5 = 6.
The item with value = 3 occurs in items1 with weight = 8 and in items2 with weight = 1, total weight = 8 + 1 = 9.
The item with value = 4 occurs in items1 with weight = 5, total weight = 5.  
Therefore, we return [[1,6],[3,9],[4,5]].

Example 2:

Input: items1 = [[1,1],[3,2],[2,3]], items2 = [[2,1],[3,2],[1,3]]
Output: [[1,4],[2,4],[3,4]]
Explanation: 
The item with value = 1 occurs in items1 with weight = 1 and in items2 with weight = 3, total weight = 1 + 3 = 4.
The item with value = 2 occurs in items1 with weight = 3 and in items2 with weight = 1, total weight = 3 + 1 = 4.
The item with value = 3 occurs in items1 with weight = 2 and in items2 with weight = 2, total weight = 2 + 2 = 4.
Therefore, we return [[1,4],[2,4],[3,4]].

Example 3:

Input: items1 = [[1,3],[2,2]], items2 = [[7,1],[2,2],[1,4]]
Output: [[1,7],[2,4],[7,1]]
Explanation:
The item with value = 1 occurs in items1 with weight = 3 and in items2 with weight = 4, total weight = 3 + 4 = 7. 
The item with value = 2 occurs in items1 with weight = 2 and in items2 with weight = 2, total weight = 2 + 2 = 4. 
The item with value = 7 occurs in items2 with weight = 1, total weight = 1.
Therefore, we return [[1,7],[2,4],[7,1]].

  Constraints:

  • 1 <= items1.length, items2.length <= 1000

  • items1[i].length == items2[i].length == 2

  • 1 <= valuei, weighti <= 1000

  • Each valuei in items1 is unique.

  • Each valuei in items2 is unique.

Solution (Java, C++, Python)

  • class Solution {
        public List<List<Integer>> mergeSimilarItems(int[][] arr1, int[][] arr2) {
            int[] cache = new int[1001];
            for (int[] num : arr1) {
                cache[num[0]] += num[1];
            }
            for (int[] num : arr2) {
                cache[num[0]] += num[1];
            }
            List<List<Integer>> result = new ArrayList<>();
            for (int i = 0; i < cache.length; i++) {
                int weight = cache[i];
                if (weight > 0) {
                    int value = i;
                    result.add(Arrays.asList(value, weight));
                }
            }
            return result;
        }
    }
    
    ############
    
    class Solution {
        public List<List<Integer>> mergeSimilarItems(int[][] items1, int[][] items2) {
            int[] cnt = new int[1010];
            for (var x : items1) {
                cnt[x[0]] += x[1];
            }
            for (var x : items2) {
                cnt[x[0]] += x[1];
            }
            List<List<Integer>> ans = new ArrayList<>();
            for (int i = 0; i < cnt.length; ++i) {
                if (cnt[i] > 0) {
                    ans.add(List.of(i, cnt[i]));
                }
            }
            return ans;
        }
    }
    
  • class Solution:
        def mergeSimilarItems(
            self, items1: List[List[int]], items2: List[List[int]]
        ) -> List[List[int]]:
            cnt = [0] * 1010
            for v, w in chain(items1, items2):
                cnt[v] += w
            return [[i, v] for i, v in enumerate(cnt) if v]
    
    ############
    
    # 2363. Merge Similar Items
    # https://leetcode.com/problems/merge-similar-items/
    
    class Solution:
        def mergeSimilarItems(self, items1: List[List[int]], items2: List[List[int]]) -> List[List[int]]:
            mp = defaultdict(int)
            
            for value, weight in items1 + items2:
                mp[value] += weight
            
            A = list(mp.items())
            A.sort(key = lambda x : x[0])
            
            return [[v, w] for v, w in A]
    
    
  • class Solution {
    public:
        vector<vector<int>> mergeSimilarItems(vector<vector<int>>& items1, vector<vector<int>>& items2) {
            int cnt[1010]{};
            for (auto& x : items1) {
                cnt[x[0]] += x[1];
            }
            for (auto& x : items2) {
                cnt[x[0]] += x[1];
            }
            vector<vector<int>> ans;
            for (int i = 0; i < 1010; ++i) {
                if (cnt[i]) {
                    ans.push_back({i, cnt[i]});
                }
            }
            return ans;
        }
    };
    
  • func mergeSimilarItems(items1 [][]int, items2 [][]int) (ans [][]int) {
    	cnt := [1010]int{}
    	for _, x := range items1 {
    		cnt[x[0]] += x[1]
    	}
    	for _, x := range items2 {
    		cnt[x[0]] += x[1]
    	}
    	for i, x := range cnt {
    		if x > 0 {
    			ans = append(ans, []int{i, x})
    		}
    	}
    	return
    }
    
  • function mergeSimilarItems(items1: number[][], items2: number[][]): number[][] {
        const count = new Array(1001).fill(0);
        for (const [v, w] of items1) {
            count[v] += w;
        }
        for (const [v, w] of items2) {
            count[v] += w;
        }
        return [...count.entries()].filter(v => v[1] !== 0);
    }
    
    
  • impl Solution {
        pub fn merge_similar_items(items1: Vec<Vec<i32>>, items2: Vec<Vec<i32>>) -> Vec<Vec<i32>> {
            let mut count = [0; 1001];
            for item in items1.iter() {
                count[item[0] as usize] += item[1];
            }
            for item in items2.iter() {
                count[item[0] as usize] += item[1];
            }
            count
                .iter()
                .enumerate()
                .filter_map(|(i, &v)| {
                    if v == 0 {
                        return None;
                    }
                    Some(vec![i as i32, v])
                })
                .collect()
        }
    }
    
    

Explain:

nope.

Complexity:

  • Time complexity : O(n).
  • Space complexity : O(n).

All Problems

All Solutions