Topic tags :- Array, Two Pointers, Sorting
Question type :- Easy
Question link : Merge Sorted Array
Note : Try yourself before seeing solution here.
Question :
You are given two integer arrays nums1 and nums2, sorted in non-decreasing order, and two integers m and n, representing the number of elements in nums1 and nums2 respectively.
Merge nums1 and nums2 into a single array sorted in non-decreasing order.
The final sorted array should not be returned by the function, but instead be stored inside the array nums1. To accommodate this, nums1 has a length of m + n, where the first m elements denote the elements that should be merged, and the last n elements are set to 0 and should be ignored. nums2 has a length of n.
Example 1:
Input: nums1 = [1,2,3,0,0,0], m = 3, nums2 = [2,5,6], n = 3
Output: [1,2,2,3,5,6]
Explanation: The arrays we are merging are [1,2,3] and [2,5,6].
The result of the merge is [1,2,2,3,5,6] with the underlined elements coming from nums1.
Example 2:
Input: nums1 = [1], m = 1, nums2 = [], n = 0
Output: [1]
Explanation: The arrays we are merging are [1] and [].
The result of the merge is [1].
Example 3:
Input: nums1 = [0], m = 0, nums2 = [1], n = 1
Output: [1]
Explanation: The arrays we are merging are [] and [1].
The result of the merge is [1].
Note that because m = 0, there are no elements in nums1. The 0 is only there to ensure the merge result can fit in nums1.
Constraints:
nums1.length == m + n
nums2.length == n
0 <= m, n <= 200
1 <= m + n <= 200
-109 <= nums1[i], nums2[j] <= 109
Follow up: Can you come up with an algorithm that runs in O(m + n) time?
Solutions : in Java
Solution 1:
class Solution {
public void merge(int[] nums1, int m, int[] nums2, int n) {
int i;
if(n!=0){
for(i=m;i<m+n;i++){
nums1[i] = nums2[i-m];
}
}
Arrays.sort(nums1);
}
}
Runtime: 1 ms
Memory Usage: 40.5 MB
Solution link : click here
Solution 2:
class Solution {
public void merge(int[] nums1, int m, int[] nums2, int n) {
for(int j=0;j<n;j++){
nums1[m+j] = nums2[j];
}
Arrays.sort(nums1);
}
}
Runtime: 0 ms
Memory Usage: 39.2 MB
Solution link : click here
Solution 3:
class Solution {
public void merge(int[] nums1, int m, int[] nums2, int n) {
int i = n-1,j = m-1,k = m+n-1;
while(i>-1 && j>-1){
if(nums1[j]>nums2[i]){
nums1[k] = nums1[j];
j--;
}else{
nums1[k] = nums2[i];
i--;
}
k--;
}if(j==-1){
while(i!=-1){
nums1[k] = nums2[i];
i--;
k--;
}
}
}
}
Runtime: 0 ms
Memory Usage: 39 MB
Solution link : click here
Solution 4:
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];
i--;
k--;
}
else {
nums1[k] = nums2[j];
j--;
k--;
}
}
while (i >= 0) {
nums1[k] = nums1[i];
i--;
k--;
}
while (j >= 0) {
nums1[k] = nums2[j];
j--;
k--;
}
}
}
Runtime: 0 ms
Memory Usage: 39 MB
Solution link : click here
Thank you
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