LeetCode 2718. Sum of Matrix After Queries

You are given an integer n and a 0-indexed 2D array queries where queries[i] = [typei, indexi, vali].

Initially, there is a 0-indexed n x n matrix filled with 0's. For each query, you must apply one of the following changes:

• if typei == 0, set the values in the row with indexi to vali, overwriting any previous values.

• if typei == 1, set the values in the column with indexi to vali, overwriting any previous values.

Return the sum of integers in the matrix after all queries are applied.

Example 1:

Input: n = 3, queries = [[0,0,1],[1,2,2],[0,2,3],[1,0,4]]Output: 23Explanation: The image above describes the matrix after each query. The sum of the matrix after all queries are applied is 23.

Example 2:

Input: n = 3, queries = [[0,0,4],[0,1,2],[1,0,1],[0,2,3],[1,2,1]]Output: 17Explanation: The image above describes the matrix after each query. The sum of the matrix after all queries are applied is 17.

最后一次会有影响，所以我们用hashmap去保存最后的数据，那么就要减减循环了。

然后依次累加。

Runtime: 24 ms, faster than 20.00% of Java online submissions for Sum of Matrix After Queries.

Memory Usage: 70.8 MB, less than 20.00% of Java online submissions for Sum of Matrix After Queries.