climbing-stairs-leetcode

climbing-stairs.java

@@ -0,0 +1,22 @@
+// https://leetcode.com/problems/climbing-stairs/
+
+public class Solution {
+ public int climbStairs(int n) {
+
+  return climb_Stairs(0, n, new int[n + 1]);
+ }
+
+ public int climb_Stairs(int i, int n, int dp[]) {
+  if (i > n) {
+   return 0;
+  }
+  if (i == n) {
+   return 1;
+  }
+  if (dp[i] > 0) {
+   return dp[i];
+  }
+  dp[i] = climb_Stairs(i + 1, n, dp) + climb_Stairs(i + 2, n, dp);
+  return dp[i];
+ }
+}