Given an integer K and an index array arr[] of length N which contains elements in the range [1, N], the task is to find the index after traversing the array by K steps starting from the index 1.
Traversal of index array: In the traversal of the index array the next index to be visited is the value at the current index.
Examples:
Input: arr[] = {3, 2, 4, 1}, K = 5
Output: 4
Explanation:
Traversal to the indices starting from index 1:
1 => 3 => 4 => 1 => 3 => 4
Finally, after K traversals the index is 4Input: arr[] = {6, 5, 2, 5, 3, 2}, K = 2
Output: 5
Approach: The key observation in the problem is that after traversing the index array N times it repeats itself. Therefore, we can find the value of the 
and then finally find the index after traversal.
Below is the implementation of the above approach:
C++
// C++ implementation to find the // index after traversing the index // array K times #include<bits/stdc++.h> using namespace std; // Function to find the index after // traversing the index array K times int findIndexAfterKTrav(vector<int> arr, int n, int k){ k = k % n; int indi = 1; // Loop to traverse the index // array K times while (k){ indi = arr[indi-1]; k--; } return arr[indi-1]; } // Driver Code int main() { int n = 4, k = 5; vector<int> arr{3, 2, 4, 1}; // Function Call cout << findIndexAfterKTrav(arr, n, k); return 0; } |
Java
// Java implementation to find the // index after traversing the index // array K times class GFG{ // Function to find the index after // traversing the index array K times public static int findIndexAfterKTrav(int[] arr, int n, int k) { k = k % n; int indi = 1; // Loop to traverse the index // array K times while (k > 0) { indi = arr[indi - 1]; k--; } return arr[indi - 1]; } // Driver code public static void main(String[] args) { int n = 4, k = 5; int[] arr = { 3, 2, 4, 1 }; // Function Call System.out.print(findIndexAfterKTrav(arr, n, k)); } } // This code is contributed by divyeshrabadiya07 |
Python3
# Python3 implementation to find the # index after traversing the index # array K times # Function to find the index after # traversing the index array K times def findIndexAfterKTrav(arr, n, k): k = k % n; indi = 1; # Loop to traverse the index # array K times while (k > 0): indi = arr[indi - 1]; k -= 1; return arr[indi - 1]; # Driver code if __name__ == '__main__': n = 4; k = 5; arr = [ 3, 2, 4, 1 ]; # Function Call print(findIndexAfterKTrav(arr, n, k)); # This code is contributed by Princi Singh |
C#
// C# implementation to find the // index after traversing the index // array K times using System; class GFG{ // Function to find the index after // traversing the index array K times public static int findIndexAfterKTrav(int[] arr, int n, int k) { k = k % n; int indi = 1; // Loop to traverse the index // array K times while (k > 0) { indi = arr[indi - 1]; k--; } return arr[indi - 1]; } // Driver code public static void Main(String[] args) { int n = 4, k = 5; int[] arr = { 3, 2, 4, 1 }; // Function Call Console.Write(findIndexAfterKTrav(arr, n, k)); } } // This code is contributed by Princi Singh |
4
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