Add house robber solution

Author: sudheerj

src/java1/algorithms/dynamicProgramming/HouseRobber.java

@@ -0,0 +1,31 @@
+package java1.algorithms.dynamicProgramming;
+
+public class HouseRobber {
+    // TC:O(n) SC:O(1)
+    private static int robber1(int[] nums) {
+        int rob1 = nums[0], rob2 = Math.max(rob1, nums[1]);
+        for(int i=2; i< nums.length; i++) {
+            int temp = Math.max(nums[i]+rob1, rob2);
+            rob1 = rob2;
+            rob2 = temp;
+        }
+        return rob2;
+    } 
+
+    // TC:O(n) SC:O(n)
+    private static int robber2(int[] nums) {
+        int[] dp = new int[nums.length];
+        dp[0] = nums[0];
+        dp[1] = nums[1];
+        for(int i=2; i<nums.length; i++) {
+            dp[i] = Math.max(nums[i] + dp[i-2], dp[i-1]);
+        }
+        return dp[nums.length-1];
+    }   
+
+    public static void main(String[] args) {
+        int[] nums = {2,7,9,3,1};
+        System.out.println(robber1(nums));
+        System.out.println(robber2(nums));
+    }
+}

src/javascript/algorithms/dynamicProgramming/houseRobber.js

@@ -0,0 +1,27 @@
+// TC:O(n) SC:O(1)
+function robber1(nums) {
+    let rob1 = nums[0], rob2 = nums[1];
+
+    for(let i=2; i<nums.length; i++) {
+        let temp = Math.max(nums[i] + rob1, rob2);
+        rob1 = rob2;
+        rob2 = temp;
+    }
+    return rob2;
+}
+
+// TC:O(n) SC:O(n)
+function robber2(nums) {
+    let dp = new Array(nums.length).fill(0);
+    dp[0] = nums[0];
+    dp[1] = nums[1];
+
+    for(let i=2; i< nums.length; i++) {
+        dp[i] = Math.max(nums[i] + dp[i-2], dp[i-1]);
+    }
+    return dp[nums.length-1];
+}
+
+let nums = [2,7,9,3,1];
+console.log(robber1(nums));
+console.log(robber2(nums));