Created
May 7, 2012 01:40
-
-
Save rvivek/2625355 to your computer and use it in GitHub Desktop.
Merge Sort
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
#include <iostream> | |
#define REP(i,N) for( int i = 0;i < N;i++ ) | |
using namespace std; | |
//Function Declarations | |
void mergeSort(int numbers[], int temp[], int array_size); | |
void m_sort(int numbers[], int temp[], int left, int right); | |
void merge(int numbers[], int temp[], int left, int mid, int right); | |
int main(){ | |
int N; cin >> N; // Read the size of the array | |
int * ar = new int[N]; | |
int * br = new int[N]; // Another array | |
REP(i,N) { cin >> ar[i]; } | |
mergeSort(ar, br, N); | |
return 0; | |
} | |
void mergeSort(int numbers[], int temp[], int array_size){ | |
m_sort(numbers, temp, 0, array_size - 1); | |
} | |
void m_sort(int numbers[], int temp[], int left, int right){ | |
int mid; | |
if (right > left){ | |
mid = (right + left) / 2; | |
m_sort(numbers, temp, left, mid); | |
m_sort(numbers, temp, (mid+1), right); | |
merge(numbers, temp, left, (mid+1), right); | |
} | |
} | |
void merge(int numbers[], int temp[], int left, int mid, int right){ | |
int i, left_end, num_elements, tmp_pos; | |
left_end = (mid - 1); | |
tmp_pos = left; | |
num_elements = (right - left + 1); | |
while ((left <= left_end) && (mid <= right)){ | |
if (numbers[left] <= numbers[mid]){ | |
temp[tmp_pos] = numbers[left]; | |
tmp_pos += 1; | |
left += 1; | |
} | |
else{ | |
temp[tmp_pos] = numbers[mid]; | |
tmp_pos += 1; | |
mid += 1; | |
} | |
} | |
while (left <= left_end){ | |
temp[tmp_pos] = numbers[left]; | |
left += 1; | |
tmp_pos += 1; | |
} | |
while (mid <= right){ | |
temp[tmp_pos] = numbers[mid]; | |
mid += 1; | |
tmp_pos += 1; | |
} | |
//modified | |
REP(i,num_elements){ | |
numbers[right] = temp[right]; | |
right--; | |
} | |
} |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment