题目
【合并两个有序数组】
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
要实现的就是将nums2的数字插入nums1中,如果从前往后,那么就涉及到元素的移动,为了省去移动的步骤,可以从后往前,因为num1后面是空的,不存在覆盖原数字的问题。
代码
class Solution {
public void merge(int[] nums1, int m, int[] nums2, int n) {
int i = m-1, j = n-1, k = m+n-1;
while(i >= 0 && j >= 0){
if(nums1[i] >nums2[j])
nums1[k--] = nums1[i--];
else
nums1[k--] = nums2[j--];
}
//处理nums2剩下的元素
while(j >= 0) {
nums1[k--] = nums2[j--];
}
}
}
提交结果
Runtime: 0 ms, faster than 100.00% of Java online submissions for Merge Sorted Array.
Memory Usage: 37.4 MB, less than 42.33% of Java online submissions for Merge Sorted Array.