leetcode 107: Climbing Stairs

Climbing StairsApr
3 '12

You are climbing a stair case. It takes n steps to reach to the top.

Each time you can either climb 1 or 2 steps. In how many distinct ways can you climb to the top?

public class Solution {
public int climbStairs(int n) {
// Start typing your Java solution below
// DO NOT write main() function

if(n==1) return 1;
int a = 1; // 1
int b = 2; // 2

int c = 0;
for(int i=3; i<=n;i++) {
c = a+b;
a = b;
b = c;
}

return b;
}
}