Given a number n, find n-th Fibonacci Number. Note that n may be large.
Input : 100 Output : 354224848179261915075 Input : 500 Output : 139423224561697880139724382870 407283950070256587697307264108962948325571622 863290691557658876222521294125
Prerequisite: BigInteger Class in Java, Fibonacci numbers
Fibonacci of large number may contain more than 100 digits, it can be easily handled by BigInteger in Java. BigInteger class is used for the mathematical operation which involves very big integer calculations that are outside the limit of all available primitive data types.
Fibonacci of 100th term is 354224848179261915075
Note that the above solution takes O(n) time, we can find the n-th Fibonacci number in O(log n) time. As an exercise, find the n-th Fibonacci number for large n in O(log n) time.
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