From b3e6c87da3a94b9ab206667f94b3777e8bff0b19 Mon Sep 17 00:00:00 2001 From: Yogesh Bhatia Date: Fri, 2 Oct 2020 13:22:14 +0530 Subject: [PATCH] Create merge_sort_cpp --- Sorting/merge_sort_cpp | 96 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 96 insertions(+) create mode 100644 Sorting/merge_sort_cpp diff --git a/Sorting/merge_sort_cpp b/Sorting/merge_sort_cpp new file mode 100644 index 0000000..5da4453 --- /dev/null +++ b/Sorting/merge_sort_cpp @@ -0,0 +1,96 @@ +#include +#include + +// Merges two subarrays of arr[]. +// First subarray is arr[l..m] +// Second subarray is arr[m+1..r] +void merge(int arr[], int l, int m, int r) +{ + int i, j, k; + int n1 = m - l + 1; + int n2 = r - m; + + /* create temp arrays */ + int L[n1], R[n2]; + + /* Copy data to temp arrays L[] and R[] */ + for (i = 0; i < n1; i++) + L[i] = arr[l + i]; + for (j = 0; j < n2; j++) + R[j] = arr[m + 1 + j]; + + /* Merge the temp arrays back into arr[l..r]*/ + i = 0; // Initial index of first subarray + j = 0; // Initial index of second subarray + k = l; // Initial index of merged subarray + while (i < n1 && j < n2) { + if (L[i] <= R[j]) { + arr[k] = L[i]; + i++; + } + else { + arr[k] = R[j]; + j++; + } + k++; + } + + /* Copy the remaining elements of L[], if there + are any */ + while (i < n1) { + arr[k] = L[i]; + i++; + k++; + } + + /* Copy the remaining elements of R[], if there + are any */ + while (j < n2) { + arr[k] = R[j]; + j++; + k++; + } +} + +/* l is for left index and r is right index of the + sub-array of arr to be sorted */ +void mergeSort(int arr[], int l, int r) +{ + if (l < r) { + // Same as (l+r)/2, but avoids overflow for + // large l and h + int m = l + (r - l) / 2; + + // Sort first and second halves + mergeSort(arr, l, m); + mergeSort(arr, m + 1, r); + + merge(arr, l, m, r); + } +} + +/* UTILITY FUNCTIONS */ +/* Function to print an array */ +void printArray(int A[], int size) +{ + int i; + for (i = 0; i < size; i++) + printf("%d ", A[i]); + printf("\n"); +} + +/* Driver program to test above functions */ +int main() +{ + int arr[] = { 12, 11, 13, 5, 6, 7 }; + int arr_size = sizeof(arr) / sizeof(arr[0]); + + printf("Given array is \n"); + printArray(arr, arr_size); + + mergeSort(arr, 0, arr_size - 1); + + printf("\nSorted array is \n"); + printArray(arr, arr_size); + return 0; +}