[leetcode]Merge Sorted Array

简单题。从尾巴开始往前就行了。

public class Solution {
    public void merge(int A[], int m, int B[], int n) {
        // Start typing your Java solution below
        // DO NOT write main() function
        int len = m + n;
        int i = m - 1;
        int j = n - 1;
        int k = len - 1;
        
        while (i >= 0 && j >= 0) {           
            if (A[i] >= B[j]) {
                A[k] = A[i];
                i--;
            } else {
                A[k] = B[j];
                j--;
            }
            
            k--;
        }
        
        int idx = i >= 0 ? i : j;
        int[] tmp = i >=0 ? A : B;
        while (idx >=0) {
            A[k] = tmp[idx];
            k--;
            idx--;
        }
    }
}