Merge pull request #62 from its-amans/main

merge_sort

DSA_Codesheet/C/merge_sort.c

@@ -0,0 +1,102 @@
+#include<conio.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+// 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
+	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;
+	j = 0;
+	k = l;
+	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[]
+	while (i < n1) {
+		arr[k] = L[i];
+		i++;
+		k++;
+	}
+
+	// Copy the remaining elements of
+	// R[]
+	while (j < n2)
+	{
+		arr[k] = R[j];
+		j++;
+		k++;
+	}
+}
+
+void mergeSort(int arr[],
+			int l, int r)
+{
+	if (l < r)
+	{
+		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);
+	}
+}
+
+// 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");
+}
+
+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;
+}