[leetCode/Javascript] 2363. Merge Similar Items

문제

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.

 

 

 

접근방향

배열을 하나로 합치고, 0인덱스 자리 수를 비교해서 1인덱스 자리수를 더해서 새로운 배열에 더하고 남은 배열을 뒤에 이어붙인다 - 라고 생각하며 코드를 썼다. 

 

 

 

 

 

코드

- 런타임 오버 실패코드

 

처음 생각했던 접근 방향으로 구구절절하게 적어내려갔던 코드. 런타임 초과했다 - 

var mergeSimilarItems = function(items1, items2) {
    const result = []
    
    const newTemp = [...items1, ...items2]

    for(let i=0; i<newTemp.length; i++){
     for(let j=i+1; j<newTemp.length; j++){
        if(newTemp[i][0] == newTemp[j][0]){
            let sum = newTemp[i][1] + newTemp[j][1]
            result.push([newTemp[i][0], sum])
            newTemp.splice(j,1)
            newTemp.splice(i,1)
             i--
             j--
            
        }
        
     }
        
    }

    return [...result, ...newTemp].sort((a,b) => a[0] - b[0])
    
    }

 

 

 

-해결코드

다른 분들의 코드를 보면서 적어내려간 코드.

var mergeSimilarItems = function(items1, items2) {
    let map =  {}
    let items = [...items1, ...items2]
    for(const [val, weight] of items) {
        if(map[val]) {
            map[val] += weight
        } else {
            map[val] = weight
        }
    }
   return Object.entries(map)
    
};

 

알고리즘 백날 풀면서 나는 뭐하는 사람인가 싶은 생각이 들었던 문제였다.