Add climbing stairs (TheAlgorithms#4168)

Rutikpatil0123 · web-flow · commit 7ed65b0a1e47 · 2023-04-28T20:34:15.000+03:00
diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/ClimbingStairs.java b/src/main/java/com/thealgorithms/dynamicprogramming/ClimbingStairs.java
@@ -0,0 +1,30 @@
+package com.thealgorithms.dynamicprogramming;
+
+/* A DynamicProgramming solution for Climbing Stairs' problem Returns the
+    distinct ways can you climb to the staircase by either climbing 1 or 2 steps.
+
+    Link : https://medium.com/analytics-vidhya/leetcode-q70-climbing-stairs-easy-444a4aae54e8
+*/
+public class ClimbingStairs {
+
+    public static int numberOfWays(int n) {
+
+        if(n == 1 || n == 0){
+            return n;
+        }
+        int prev = 1;
+        int curr = 1;
+
+        int next;
+
+        for(int i = 2; i <= n; i++){
+            next = curr+prev;
+            prev = curr;
+
+            curr = next;
+        }
+
+        return curr;
+
+    }
+}
diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/climbStairsTest.java b/src/test/java/com/thealgorithms/dynamicprogramming/climbStairsTest.java
@@ -0,0 +1,24 @@
+package com.thealgorithms.dynamicprogramming;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+
+public class climbStairsTest {
+
+    @Test
+    void climbStairsTestForTwo(){assertEquals(2, ClimbingStairs.numberOfWays(2));}
+
+    @Test
+    void climbStairsTestForZero(){assertEquals(0, ClimbingStairs.numberOfWays(0));}
+
+    @Test
+    void climbStairsTestForOne(){assertEquals(1, ClimbingStairs.numberOfWays(1));}
+
+    @Test
+    void climbStairsTestForFive(){assertEquals(8, ClimbingStairs.numberOfWays(5));}
+
+    @Test
+    void climbStairsTestForThree(){assertEquals(3, ClimbingStairs.numberOfWays(3));}
+}
