refactor 70

fishercoder1534 · fishercoder1534 · commit b63d7b71e128 · 2018-02-02T08:52:09.000-08:00
diff --git a/src/main/java/com/fishercoder/solutions/_70.java b/src/main/java/com/fishercoder/solutions/_70.java
@@ -1,29 +1,53 @@
 package com.fishercoder.solutions;
 
-/**Leetcode 70: You are climbing a stair case. It takes n steps to reach to the top.
+/**
+ * 70. Climbing Stairs
+
+ 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
+
+ */
 
-Each time you can either climb 1 or 2 steps. In how many distinct ways can you climb to the top?*/
 public class _70 {
+  public static class Solution1 {
     //classical dp problem
     public int climbStairs(int n) {
-        if (n < 1) {
-            return 0;
-        }
-        if (n < 4) {
-            return n;
-        }
+      if (n < 1) {
+        return 0;
+      } else if (n < 4) {
+        return n;
+      } else {
         int[] dp = new int[n + 1];
         //the number of ways to reach step n could be calculated from n-1 and n-2
         dp[1] = 1;
         dp[2] = 2;
         for (int i = 3; i <= n; i++) {
-            dp[i] = dp[i - 1] + dp[i - 2];
+          dp[i] = dp[i - 1] + dp[i - 2];
         }
         return dp[n];
+      }
     }
-
-    public static void main(String... strings) {
-        _70 test = new _70();
-        System.out.println(test.climbStairs(6));
-    }
+  }
 }
