TernarySearch.cpp

#include <stdio.h> 
int ternarySearch(int l, int r, int key, int ar[]) 
{ 
	if (r >= l) { 
		int mid1 = l + (r - l) / 3; 
		int mid2 = r - (r - l) / 3; 
		if (ar[mid1] == key) { 
			return mid1; 
		} 
		if (ar[mid2] == key) { 
			return mid2; 
		} 
		if (key < ar[mid1]) { 

			return ternarySearch(l, mid1 - 1, key, ar); 
		} 
		else if (key > ar[mid2]) { 

			return ternarySearch(mid2 + 1, r, key, ar); 
		} 
		else { 

			return ternarySearch(mid1 + 1, mid2 - 1, key, ar); 
		} 
	} 

	return -1; 
} 

int main() 
{ 
	int l, r, p, key; 
	int ar[] = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 }; 

	l = 0; 
	r = 9; 
	key = 5; 

	p = ternarySearch(l, r, key, ar); 

	printf("Index of %d is %d\n", key, p); 
	key = 50; 
	p = ternarySearch(l, r, key, ar); 

	printf("Index of %d is %d", key, p); 
}