9. Merge Sorted Array

Topic :

arrays

Difficulty :

easy

Problem Link :

problem statement

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

solution

// merge two sorted arrays and dont use any extra space //

import java.io.*;
import java.util.*;
class Merge_Two_Sorted_Arrays
{
    static void merge (int a[],int b[])
    { 
        int m=a.length;
        int n=b.length;

        for(int i=0;i<m;i++)
        { if (a[i]>b[0])
            { int temp=a[i];
                a[i]=b[0];
                b[0]=temp;

                int first=b[0];
                int k;
                for ( k=1;k<n && b[k]<first;k++) // sorting the second  array back in order
                { b[k-1]=b[k];
                }
                b[k-1]=first;
            }
        }
    }

    public static void main(String args[])
    { 
        int a[]={1,4,7,8,10};
        int b[]={2,3,9};

        merge(a,b);

        for(int i=0;i<a.length;i++)
            System.out.print(a[i]+" ");

        for(int i=0;i<b.length;i++)
            System.out.print(b[i]+" ");

    }
}