Add C++ implementation

Signed-off-by: begeekmyfriend <begeekmyfriend@gmail.com>

Author: begeekmyfriend

198_house_robber/robber.c

@@ -9,20 +9,15 @@ static inline int max(int a, int b)
 
 static int rob(int* nums, int numsSize)
 {
-    if (numsSize == 0) {
-        return 0;
-    }
-
     int i;
-    int taken = nums[0];
+    int taken = 0;
     int untaken = 0;
     /* Record max profits of nums[0...i] respectively */
-    for (i = 1; i < numsSize; i++) {
+    for (i = 0; i < numsSize; i++) {
         int tmp_taken = taken;
-        int tmp_untaken = untaken;
         /* Taken or untaken nums[i] */
         taken = untaken + nums[i];
-        untaken = max(tmp_taken, tmp_untaken);
+        untaken = max(tmp_taken, untaken);
     }
 
     return max(taken, untaken);

213_house_robber_ii/robber.c

@@ -10,25 +10,22 @@ static inline int max(int a, int b)
 static int _rob(int* nums, int numsSize)
 {
     int i;
-    int taken = nums[0];
+    int taken = 0;
     int untaken = 0;
     /* Record max profits of nums[0...i] respectively */
-    for (i = 1; i < numsSize; i++) {
+    for (i = 0; i < numsSize; i++) {
         int tmp_taken = taken;
-        int tmp_untaken = untaken;
         /* Taken or untaken nums[i] */
-        taken = tmp_untaken + nums[i];
-        untaken = max(tmp_taken, tmp_untaken);
+        taken = untaken + nums[i];
+        untaken = max(tmp_taken, untaken);
     }
 
     return max(taken, untaken);
 }
 
 static int rob(int* nums, int numsSize)
 {
-    if (numsSize == 0) {
-        return 0;
-    } else if (numsSize == 1) {
+    if (numsSize == 1) {
         return nums[0];
     } else {
         /* The first and the last element are adjacent */

337_house_robber_iii/robber.cc

@@ -0,0 +1,31 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+/**
+ * Definition for a binary tree node.
+ * struct TreeNode {
+ *     int val;
+ *     TreeNode *left;
+ *     TreeNode *right;
+ *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
+ * };
+ */
+class Solution {
+public:
+    int rob(TreeNode* root) {
+        auto res = dfs(root);
+        return max(res.first, res.second);
+    }
+
+    pair<int, int> dfs(TreeNode *root) {
+        if (root == nullptr) {
+            return make_pair(0, 0);
+        }
+        auto subl = dfs(root->left);
+        auto subr = dfs(root->right);
+        int taken = root->val + subl.second + subr.second;
+        int untaken = max(subl.first, subl.second) + max(subr.first, subr.second);
+        return make_pair(taken, untaken);
+    }
+};