Accepted

Author: gouthampradhan

problems/src/ClimbingStairs.java

@@ -0,0 +1,27 @@
+/**
+ * Created by gouthamvidyapradhan on 01/04/2017.
+ */
+public class ClimbingStairs
+{
+    /**
+     * Main method
+     * @param args
+     * @throws Exception
+     */
+    public static void main(String[] args) throws Exception
+    {
+
+    }
+
+    public int climbStairs(int n)
+    {
+        if(n == 0 || n == 1) return 1;
+        int[] A = new int[n + 1];
+        A[n] = 1;
+        A[n - 1] = 1;
+        for(int i = n - 2; i >= 0; i --)
+            A[i] = A[i + 1] +  A[i + 2];
+        return A[0];
+    }
+
+}

problems/src/DecodeWays.java

@@ -0,0 +1,46 @@
+import java.util.PriorityQueue;
+import java.util.Queue;
+
+/**
+ * Created by gouthamvidyapradhan on 01/04/2017.
+ * Accepted
+ */
+public class DecodeWays
+{
+    /**
+     * Main method
+     * @param args
+     * @throws Exception
+     */
+    public static void main(String[] args) throws Exception
+    {
+        System.out.println(new DecodeWays().numDecodings("3120"));
+    }
+
+    public int numDecodings(String s)
+    {
+        if(s == null || s.isEmpty()) return 0;
+        int[] dp = new int[s.length() + 2];
+        dp[s.length()] = 1;
+        dp[s.length() + 1] = 1;
+        for(int i = s.length() - 1; i >= 0; i --)
+        {
+            for(int j = i + 1; j < i + 3; j ++)
+            {
+                if(j <= s.length())
+                {
+                    String subStr = s.substring(i, j);
+                    if(!subStr.startsWith("0"))
+                    {
+                        int intVal = Integer.parseInt(subStr);
+                        if(intVal <= 26)
+                        {
+                            dp[i] += dp[j];
+                        }
+                    }
+                }
+            }
+        }
+        return dp[0];
+    }
+}