AlgoDesignAndTechniqueEdxJava/sources/FibLastDigit.java


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import java.util.Scanner;

public class FibLastDigit {

	public static int lastDigitNaive(int n) {
		if (n <= 1)
			return n;
		return (lastDigitNaive(n - 1) + lastDigitNaive(n - 2)) % 10;
	}

	public static int lastDigitOptimized(int n) {
		if (n <= 1)
			return n;
		final int[] fibLastDigitArray = new int[n + 1];
		fibLastDigitArray[0] = 0;
		fibLastDigitArray[1] = 1;
		for (int i = 2; i < n + 1; i++) {
			fibLastDigitArray[i] = (fibLastDigitArray[i - 1] + fibLastDigitArray[i - 2]) % 10;
		}
		return fibLastDigitArray[n];
	}

	public static void main(String[] args) {
		Scanner in = new Scanner(System.in);
		int n = in.nextInt();

		System.out.println(lastDigitOptimized(n));
	}

}