0%

Leetcode088-mergeSortedArray

Description

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

1
2
3
4
5
Input:
nums1 = [1,2,3,0,0,0], m = 3
nums2 = [2,5,6], n = 3

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

Solution

Solution: best solution

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
class Solution {
public void merge(int[] nums1, int m, int[] nums2, int n) {
int i = m - 1;
int j = n - 1;
int k = m + n -1;
while (i >= 0 && j >= 0){
if (nums1[i] > nums2[j]){
nums1[k--] = nums1[i--];
}
else
nums1[k--] = nums2[j--];
}
while (i >= 0)
nums1[k--] = nums1[i--];
while (j >= 0)
nums1[k--] = nums2[j--];
}
}

Solution 2: Not a good solution

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
class Solution {
public void merge(int[] nums1, int m, int[] nums2, int n) {
if (n == 0) return;
int[] tmp = new int[n + m];
int i = 0;
int j = 0;
int index = 0;
while (i < m && j < n){
if (nums1[i] <= nums2[j]){
tmp[index++] = nums1[i++];
}
else{
tmp[index++] = nums2[j++];
}
}
if (i < m)
for (int k = i; i < m; k++) tmp[index++] = nums1[i++];
if (j < n)
for (int k = j; j < n; k++) tmp[index++] = nums2[j++];
for (int k = 0; k < m + n; k++)
nums1[k] = tmp[k];
}
}