Climbing Stairs.java

class Solution {
  int climbStairs(int n) {
    int[] dp = new int[n+1];
    dp[0] = 1;
    dp[1] = 1;
    for (int i = 2; i < n+1; i++) {
        dp[i] = dp[i-1] + dp[i-2];
    }
    return dp[n];
    }
}