FilesExpand file tree

 master

/

Fibonacci.java

Copy path

Blame

More file actions

Blame

More file actions

Latest commit

 

History

History

History

75 lines (58 loc) · 1.7 KB

 master

/

Fibonacci.java

Copy path

Top

File metadata and controls

• Code
• Blame

75 lines (58 loc) · 1.7 KB

Raw

Copy raw file

Download raw file

Open symbols panel

Edit and raw actions

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

47

48

49

50

51

52

53

54

55

56

57

58

59

60

61

62

63

64

65

66

67

68

69

70

71

72

73

74

import java.io.BufferedReader;

import java.io.InputStreamReader;

import java.util.HashMap;

import java.util.Map;

/**

*

* @author Varun Upadhyay (https://github.com/varunu28)

*

*/

public class Fibonacci {

private static Map<Integer,Integer> map = new HashMap<Integer,Integer>();

public static void main(String[] args) throws Exception {

BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

int n = Integer.parseInt(br.readLine());

System.out.println(fibMemo(n)); // Returns 8 for n = 6

System.out.println(fibBotUp(n)); // Returns 8 for n = 6

}

/**

* This method finds the nth fibonacci number using memoization technique

*

* @param n The input n for which we have to determine the fibonacci number

* Outputs the nth fibonacci number

**/

private static int fibMemo(int n) {

if (map.containsKey(n)) {

return map.get(n);

}

int f;

if (n <= 2) {

f = 1;

}

else {

f = fibMemo(n-1) + fibMemo(n-2);

map.put(n,f);

}

return f;

}

/**

* This method finds the nth fibonacci number using bottom up

*

* @param n The input n for which we have to determine the fibonacci number

* Outputs the nth fibonacci number

**/

private static int fibBotUp(int n) {

Map<Integer,Integer> fib = new HashMap<Integer,Integer>();

for (int i=1;i<n+1;i++) {

int f = 1;

if (i<=2) {

f = 1;

}

else {

f = fib.get(i-1) + fib.get(i-2);

}

fib.put(i, f);

}

return fib.get(n);

}

}