技術標籤：演算法&資料結構

題目描述：

https://leetcode-cn.com/problems/sum-of-even-numbers-after-queries/

Java程式碼：

class Solution {
    public int[] sumEvenAfterQueries(int[] A, int[][] queries) {
        int[] ans=new int[queries.length];
        int evenSum=0,cnt=0;
        for(int a:A)if((a&1)==0)evenSum+=a;
        for(int[] vi:queries){
            if((A[vi[1]]&1)==0)evenSum-=A[vi[1]];
            A[vi[1]]+=vi[0];
            if((A[vi[1]]&1)==0)evenSum+=A[vi[1]];
            ans[cnt++]=evenSum;
        }
        return ans;
    }
}