88.Merge-Sorted-Array

88. Merge Sorted Array

题目地址

https://www.lintcode.com/problem/merge-sorted-array/description

https://leetcode.com/problems/merge-sorted-array/

题目描述

Given two sorted integer arrays nums1 and nums2, merge nums2 into nums1 as one sorted array.

Note:
The number of elements initialized in nums1 and nums2 are m and n respectively.
You may assume that nums1 has enough space (size that is greater or equal to m + n) to hold additional elements from nums2.

Example:
Input:
nums1 = [1,2,3,0,0,0], m = 3
nums2 = [2,5,6],       n = 3

Output: [1,2,2,3,5,6]

代码

Approach #1 Two Pointers

public class Solution {
    public void mergeSortedArray (int[] A, int m, int[] B, int n) {
   if (A == null || B == null) return;

    int index = m + n - 1;
    while (m > 0 && n > 0) {
      if (A[m - 1] > B[n - 1]) {
        A[index] = A[m - 1];
        m--;
      } else {
        A[index] = A[n - 1];
        n--;
      }
      index--;
    }
    while (n > 0) {
      A[index] = B[n - 1];
      n--;
      index--;
    }
  }
}