_985.java

package com.fishercoder.solutions;

/**
 * 985. Sum of Even Numbers After Queries
 *
 * We have an array A of integers, and an array queries of queries.
 * For the i-th query val = queries[i][0], index = queries[i][1], we add val to A[index].  Then, the answer to the i-th query is the sum of the even values of A.
 * (Here, the given index = queries[i][1] is a 0-based index, and each query permanently modifies the array A.)
 * Return the answer to all queries.  Your answer array should have answer[i] as the answer to the i-th query.
 *
 * Example 1:
 *
 * Input: A = [1,2,3,4], queries = [[1,0],[-3,1],[-4,0],[2,3]]
 * Output: [8,6,2,4]
 * Explanation:
 * At the beginning, the array is [1,2,3,4].
 * After adding 1 to A[0], the array is [2,2,3,4], and the sum of even values is 2 + 2 + 4 = 8.
 * After adding -3 to A[1], the array is [2,-1,3,4], and the sum of even values is 2 + 4 = 6.
 * After adding -4 to A[0], the array is [-2,-1,3,4], and the sum of even values is -2 + 4 = 2.
 * After adding 2 to A[3], the array is [-2,-1,3,6], and the sum of even values is -2 + 6 = 4.
 *
 * Note:
 *
 * 1 <= A.length <= 10000
 * -10000 <= A[i] <= 10000
 * 1 <= queries.length <= 10000
 * -10000 <= queries[i][0] <= 10000
 * 0 <= queries[i][1] < A.length
 */
public class _985 {
  public static class Solution1 {
    public int[] sumEvenAfterQueries(int[] A, int[][] queries) {
      int[] result = new int[A.length];
      for (int i = 0; i < A.length; i++) {
        int col = queries[i][1];
        A[col] = A[col] + queries[i][0];
        result[i] = computeEvenSum(A);
      }
      return result;
    }

    private int computeEvenSum(int[] A) {
      int sum = 0;
      for (int num : A) {
        if (num % 2 == 0) {
          sum += num;
        }
      }
      return sum;
    }
  }
}