Merge pull request #534 from ary1405/ary1405

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Author: probot-auto-merge[bot]

ternary search.c

@@ -0,0 +1,85 @@
+// C program to illustrate 
+// recursive approach to ternary search 
+
+#include <stdio.h> 
+
+// Function to perform Ternary Search 
+int ternarySearch(int l, int r, int key, int ar[]) 
+{ 
+	if (r >= l) { 
+
+		// Find the mid1 and mid2 
+		int mid1 = l + (r - l) / 3; 
+		int mid2 = r - (r - l) / 3; 
+
+		// Check if key is present at any mid 
+		if (ar[mid1] == key) { 
+			return mid1; 
+		} 
+		if (ar[mid2] == key) { 
+			return mid2; 
+		} 
+
+		// Since key is not present at mid, 
+		// check in which region it is present 
+		// then repeat the Search operation 
+		// in that region 
+
+		if (key < ar[mid1]) { 
+
+			// The key lies in between l and mid1 
+			return ternarySearch(l, mid1 - 1, key, ar); 
+		} 
+		else if (key > ar[mid2]) { 
+
+			// The key lies in between mid2 and r 
+			return ternarySearch(mid2 + 1, r, key, ar); 
+		} 
+		else { 
+
+			// The key lies in between mid1 and mid2 
+			return ternarySearch(mid1 + 1, mid2 - 1, key, ar); 
+		} 
+	} 
+
+	// Key not found 
+	return -1; 
+} 
+
+// Driver code 
+int main() 
+{ 
+	int l, r, p, key; 
+
+	// Get the array 
+	// Sort the array if not sorted 
+	int ar[] = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 }; 
+
+	// Starting index 
+	l = 0; 
+
+	// length of array 
+	r = 9; 
+
+	// Checking for 5 
+
+	// Key to be searched in the array 
+	key = 5; 
+
+	// Search the key using ternarySearch 
+	p = ternarySearch(l, r, key, ar); 
+
+	// Print the result 
+	printf("Index of %d is %d\n", key, p); 
+
+	// Checking for 50 
+
+	// Key to be searched in the array 
+	key = 50; 
+
+	// Search the key using ternarySearch 
+	p = ternarySearch(l, r, key, ar); 
+
+	// Print the result 
+	printf("Index of %d is %d", key, p); 
+}