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Added MergeSort Implementation in Java (#28042)

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* Added MergeSort Implementation in Java

* fix: changed c++ to cpp
This commit is contained in:
Aditya Oli
2019-06-26 05:53:35 +12:00
committed by Randell Dawson
parent cbc2c0b7c2
commit c9d00827c4
1 changed files with 73 additions and 0 deletions
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guide/english/algorithms/sorting-algorithms/merge-sort/index.md
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@ -455,6 +455,79 @@ end
```
### Implementation in Java
```Java
class MergeSort
{
void merge(int arr[], int l, int m, int r)
{
int n1 = m - l + 1;
int n2 = r - m;
int L[] = new int [n1];
int R[] = new int [n2];
for (int i=0; i<n1; ++i)
L[i] = arr[l + i];
for (int j=0; j<n2; ++j)
R[j] = arr[m + 1+ j];
int i = 0, j = 0;
int k = l;
while (i < n1 && j < n2)
{
if (L[i] <= R[j])
{
arr[k] = L[i];
i++;
}
else
{
arr[k] = R[j];
j++;
}
k++;
}
while (i < n1)
{
arr[k] = L[i];
i++;
k++;
}
while (j < n2)
{
arr[k] = R[j];
j++;
k++;
}
}
void sort(int arr[], int l, int r)
{
if (l < r)
{
int m = (l+r)/2;
sort(arr, l, m);
sort(arr , m+1, r);
merge(arr, l, m, r);
}
}
static void printArray(int arr[])
{
int n = arr.length;
for (int i=0; i<n; ++i)
System.out.print(arr[i] + " ");
System.out.println();
}
public static void main(String args[])
{
int arr[] = {12, 11, 13, 5, 6, 7};
System.out.println("Given Array");
printArray(arr);
MergeSort ob = new MergeSort();
ob.sort(arr, 0, arr.length-1);
System.out.println("\n The Sorted array is : ");
printArray(arr);
}
}
```
### Relavant videos on freeCodeCamp YouTube channel
* <a href='https://youtu.be/TzeBrDU-JaY'>Merge Sort algorithm - MyCodeSchool</a>