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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?
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public class Solution {
public int climbStairs(int n) {
if(n==1) return 1;
if(n==2) return 2;
return climbStairs(n-1) + climbStairs(n-2);
}
}
递归，结果超时。
遂动态规划。
1 public class Solution { 2 public int climbStairs(int n) { 3 if(n < 4) return n; 4 int a = 2, b = 3, c=5; 5 for(int i = 4; i <n;i++){ 6 c = a + b; 7 a = c - a; 8 b = c; 9 c = a + b; 10 } 11 return c; 12 } 13 }
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原文地址：http://www.cnblogs.com/guoguolan/p/5382129.html
