LeetCode-985 Sum of Even Numbers After Queries Solution (with Java)

1. Description:

Notes:

2. Examples:

3.Solutions:

 1 /**
 2  * Created by sheepcore on 2019-02-24
 3  */
 4 class Solution {
 5    public int[] sumEvenAfterQueries(int[] A, int[][] queries) {
 6         int sum = 0;
 7         for (int a : A) {
 8             if (a % 2 == 0)
 9                 sum += a;
10         } // sum of even #s.
11         int[] ans = new int[queries.length];
12         for (int i = 0; i < ans.length; ++i) {
13             int idx = queries[i][1];
14             if (A[idx] % 2 == 0) {
15                 sum -= A[idx];
16             } // from 1) and 2)
17             A[idx] += queries[i][0];
18             if (A[idx] % 2 == 0) {
19                 sum += A[idx];
20             } // from 2) and 3)
21             ans[i] = sum;
22         }
23         return ans;
24     }
25 }