/* * This is a divide and conquer algorithm. * It does this by dividing the search space by 3 parts and * using its property (usually monotonic property) to find * the desired index. * * Time Complexity : O(log3 n) * Space Complexity : O(1) (without the array) */ #include using namespace std; /* * The absolutePrecision can be modified to fit preference but * it is recommended to not go lower than 10 due to errors that * may occur. * * The value of _target should be decided or can be decided later * by using the variable of the function. */ #define _target 10 #define absolutePrecision 10 #define MAX 10000000 int N = 21; int A[MAX] = {1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,2,3,4,10}; /* * get_input function is to receive input from standard IO */ void get_input() { // TODO: Get input from STDIO or write input to memory as done above. } /* * This is the iterative method of the ternary search which returns the index of the element. */ int it_ternary_search(int left, int right, int A[],int target) { while (1) { if(left A[twoThird]) left = twoThird+1; else if(target < A[oneThird]) right = oneThird-1; else left = oneThird+1, right = twoThird-1; } else return -1; } } /* * This is the recursive method of the ternary search which returns the index of the element. */ int rec_ternary_search(int left, int right, int A[],int target) { if(left A[twoThird]) return rec_ternary_search(twoThird+1, right, A, target); return rec_ternary_search(oneThird+1, twoThird-1, A, target); } else return -1; } /* * ternary_search is a template function * You could either use it_ternary_search or rec_ternary_search according to preference. */ void ternary_search(int N,int A[],int target) { cout << it_ternary_search(0,N-1,A,target) << '\t'; cout << rec_ternary_search(0,N-1,A,target) << '\t'; cout << '\n'; } int main() { get_input(); ternary_search(N,A,_target); return 0; }