Merge Sorted Array

Problem

Given two sorted integer arrays A and B, merge B into A as one sorted array.

Example

A = [1, 2, 3, empty, empty], B = [4, 5]

After merge, A will be filled as [1, 2, 3, 4, 5]

Note

You may assume that A has enough space (size that is greater or equal to m + n) to hold additional elements from B. The number of elements initialized in A and B are m and n respectively.

Code - Java

class Solution {
    /**
     * @param A: sorted integer array A which has m elements,
     *           but size of A is m+n
     * @param B: sorted integer array B which has n elements
     * @return: void
     */
    public void mergeSortedArray(int[] A, int m, int[] B, int n) {
        int i = m - 1;
        int j = n - 1;
        for (int k = m + n - 1; k >= 0; k--) {
            if (i == -1) {
                A[k] = B[j--];
            } else if (j == -1) {
                A[k] = A[i--];
            } else if (A[i] > B[j]) {
                A[k] = A[i--];
            } else {
                A[k] = B[j--];
            }
        }
    }
}