Problem:
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.
Example 1:
Input: 2
Output: 2
Explanation: There are two ways to climb to the top.
1. 1 step + 1 step
2. 2 steps
Example 2:
Input: 3
Output: 3
Explanation: There are three ways to climb to the top.
1. 1 step + 1 step + 1 step
2. 1 step + 2 steps
3. 2 steps + 1 step
思路：
Solution (C++):
int climbStairs(int n) {
if ( n == 1 ) return 1;
vector<int> dp(n, 0);
dp[0] = 1; dp[1] = 2;
for (int i = 2; i < n; ++i) {
dp[i] = dp[i-1] + dp[i-2];
}
return dp[n-1];
}
性能：
Runtime: 0 ms Memory Usage: 6.2 MB
思路：
Solution (C++):
性能：
Runtime: ms Memory Usage: MB
