题目描述
Given two sorted integer arrays nums1 and nums2, merge nums2 into nums1 as one sorted array.
简而言之：合并两个数组到数组1中，数组1 有足够大的空间。
Note:
- The number of elements initialized in nums1 and nums2 are m and nrespectively.
- 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]
解题思路
从后向前遍历，大的在后边，能率先确认下来。
比较两个数组最后的元素，较大的放到数组1的末尾，同时，较大数组的下标减减。
题解
public void merge(int[] nums1, int m, int[] nums2, int n) {
// 从后向前的写法
int i = m-1;
int j = n-1;
int tail = m+n-1;
while(i >= 0 && j >= 0 ){
if(nums1[i] > nums2[j]){
nums1[tail] = nums1[i];
tail--;
i--;
}
else{
nums1[tail--] = nums2[j--];
}
}
while(j >= 0){
nums1[tail--] = nums2[j--];
}
}
