题目
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?
Note: Given n will be a positive integer.
解题思路
1个台阶有1种方案
2个台阶有2种方案
3个台阶有3=2+1种方案
...
n个台阶有f(n) = f(n-1) + f(n-2)种方案
使用递归的话会超时，所以使用循环计算
代码
func climbStairs(n int) int {
if 1 == n {
return 1
} else if 2 == n {
return 2
}
ret1 := 1
ret2 := 2
var ret int
for i := 2; i < n; i++ {
ret = ret1 + ret2
ret1 = ret2
ret2 = ret
}
return ret
}
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