Given a number n, find n-th Fibonacci Number. Note that n may be large.
Input : 100 Output : 218922995834555169026 Input : 500 Output : 8616829160023845073278831216566478809594 1068326060883324529903470149056115823592 713458328176574447204501
Fibonacci of large number may contain more than 100 digits, it can be easily handled by BigInteger in Java. BigInteger class is used for mathematical operation which involves very big integer calculations that are outside the limit of all available primitive data types.
268638100244853593861467272021429239676 166093189869523401231759976179817002478 816893383696544833565641918278561614433 563129766736422103503246348504103776803 673341511728991697231970827639856157644 50078474174626
Note that the above solution takes O(n) time, we can find n-th Fibonacci number in O(Log n) time. As an exercise, find n-th Fibonacci number for large n in O(Log n) time.
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