leetcode:Merge Sroted Array II

1、

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

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

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

2、

　　

public static void mergeSortedArray(int[] A,int m,int n, int[] B) {
        int i = m-1, j = n-1, index = m + n - 1;
        //从大到小
        while (i >= 0 && j >= 0) {
            if (A[i] > B[j]) {
                A[index--] = A[i--];
            } else {
                A[index--] = B[j--];
            }
        }
        while (i >= 0) {
            A[index--] = A[i--];
        }
        while (j >= 0) {
            A[index--] = B[j--];
        }
    }