88. Merge Sorted Array【Easy】【双指针-不用额外空间归并两个有序数组】

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于 2019-02-24 19:19:00 发布

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文章标签： java

原文链接：http://www.cnblogs.com/Roni-i/p/10427472.html

本文介绍了一种将两个已排序的整数数组合并成一个有序数组的方法。通过一个具体实例，展示了如何利用双指针技巧在O(m+n)的时间复杂度内完成合并过程，其中m和n分别表示两个数组的初始元素数量。

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]

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class Solution {
    public void merge(int[] A, int m, int[] B, int n) {
        int i = m - 1, j = n - 1, k = m + n - 1;
        while(i>=0 && j>=0) A[k--] = (A[i]>B[j]) ? A[i--] : B[j--];
        while(j>=0) A[k--] = B[j--];
    }
}