[Leetcode]-- Merge Sorted Array

 

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

Note:
You may assume that A has enough space to hold additional elements from B. The number of elements initialized in A and B are m and nrespectively.

public class Solution {
    public void merge(int A[], int m, int B[], int n) {
      int k = m+n-1;
      int aIdx = m-1;
      int bIdx = n-1;
      
      while(aIdx >= 0 && bIdx >=0){
          if(A[aIdx] >= B[bIdx]){
              A[k] = A[aIdx];
              aIdx--;
          }else{
              A[k] = B[bIdx];
              bIdx--;
          }
          k--;
      }
      
      // eg1: A={1,2,3}, B={4,5}   B 先遍历完 跳出循环 因为长度正好是 m+n. 所以A不用再遍历了
      // eg2: A={4,5}, B={1,2,3}  A遍历完 B还没遍历完 跳入下面循环
      while(bIdx >= 0){
          A[k] = B[bIdx];
          bIdx--;
          k--;
      }
    }
}