Find the Nth number in Fibonacci sequence.
A Fibonacci sequence is defined as follow:
The first ten numbers in Fibonacci sequence is:
0, 1, 1, 2, 3, 5, 8, 13, 21, 34 ...
Note
The Nth fibonacci number won‘t exceed the max value of signed 32-bit integer in the test cases.
网站上其实说这是naive级的题，没啥太多可说的，也许为一点改进就是常数空间复杂度吧，但是也比较清晰。
class Solution { /** * @param n: an integer * @return an integer f(n) */ public int fibonacci(int n) { // write your code here if(n == 1) return 0; if(n == 2) return 1; int num1 = 0; int num2 = 1; int num3 = 0; for(int i = 3; i <= n; i++){ num3 = num2 + num1; num1 = num2; num2 = num3; } return num3; } }
原文：http://www.cnblogs.com/goblinengineer/p/5197836.html