0088._Merge_Sorted_Array.md

88.Merge Sorted Array

难度Easy

刷题内容

原题连接

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

内容描述

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]

思路 - 时间复杂度: O(n)- 空间复杂度: O(1)******

由于数组是已经排序好的，我们可以用两个指针 i，j 指向两个数组的第一个元素，当nums[i] < nums[j],++i。否则就 ++j,并把j所指向的元素插入nums1。不过要注意这两个数组的长度。

class Solution {
public:
    void merge(vector<int>& nums1, int m, vector<int>& nums2, int n) {
        int i = 0,j = 0;
        while((i < m) && (j < n))
        {
            if(nums1[i] < nums2[j])
                i++;
            else
            {
                nums1.insert(nums1.begin() + i,nums2[j++]);
                i++;
                m++;
            }
        }
        if(j < n)
        {
            nums1.erase(nums1.begin() + m,nums1.end());
            nums1.insert(nums1.end(),nums2.begin() + j,nums2.begin() + n);
        }
        else
            nums1.erase(nums1.begin() + m,nums1.end());
    }
};