Add C++ implementation

Signed-off-by: begeekmyfriend <[email protected]>

Author: begeekmyfriend

0297_serialize_and_deserialize_binary_tree/tree_serdes.c

@@ -1,4 +1,4 @@
-#include <stdbool.h>
+#include <limits.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -10,52 +10,37 @@ struct TreeNode {
     struct TreeNode *right;
 };
 
+static int count = 0;
+static int SYM_NULL = INT_MIN;
+
 static void ser(struct TreeNode *root, char **str, int *len) {
     if (root == NULL) {
-        (*str)[(*len)++] = '#';
-        (*str)[(*len)++] = ',';
+        memcpy(str + *len, &SYM_NULL, sizeof(int));
+        (*len) += sizeof(int);
     } else {
-        int v = root->val;
-        if (v < 0) {
-            v = -v;
-            (*str)[(*len)++] = '-';
-        }
-        while (v > 0) {
-            (*str)[(*len)++] = v % 10 + '0';
-            v /= 10;
-        }
-        (*str)[(*len)++] = ',';
+        memcpy(str + *len, &root->val, sizeof(int));
+        (*len) += sizeof(int);
         ser(root->left, str, len);
         ser(root->right, str, len);
     }
+    count++;
 }
 
-static struct TreeNode *des(char **str) {
-    if (**str == '\0') {
+static struct TreeNode *des(char **str)
+{
+    if (count == 0) {
         return NULL;
     }
-    if (**str == '#') {
-        (*str)++;
-        (*str)++;
+    count--;
+
+    int value;
+    memcpy(&value, *str, sizeof(int));
+    (*str) += sizeof(int);
+    if (value == SYM_NULL) {
         return NULL;
     }
-
-    int i;
-    bool sign = false;
     struct TreeNode *node = malloc(sizeof(struct TreeNode));
-    node->val = 0;
-    if (**str == '-') {
-        sign = true;
-        (*str)++;
-    }
-    for (i = 1; **str != ','; i *= 10) {
-        node->val += i * ((**str) - '0');
-        (*str)++;
-    }
-    if (sign) {
-        node->val = -node->val;
-    }
-    (*str)++;
+    node->val = value;
     node->left = des(str);
     node->right = des(str);    
     return node;

0297_serialize_and_deserialize_binary_tree/tree_serdes.cc

@@ -0,0 +1,73 @@
+#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 Codec {
+public:
+
+    // Encodes a tree to a single string.
+    string serialize(TreeNode* root) {
+        string res;
+        ser(root, res);
+        return res;
+    }
+
+    // Decodes your encoded data to tree.
+    TreeNode* deserialize(string data) {
+        int len = data.length();
+        return des(data.c_str(), &len);
+    }
+
+private:
+    void ser(TreeNode* root, string& res) {
+        if (root == nullptr) {
+            res.push_back((char) 0x80);
+            res.push_back((char) 0x00);
+            res.push_back((char) 0x00);
+            res.push_back((char) 0x00);
+            return;
+        }
+
+        ser(root->left, res);
+        ser(root->right, res);
+
+        for (int i = sizeof(int) - 1; i >= 0; i--) {
+            res.push_back(((char *)&root->val)[i]);
+        }
+    }
+    
+    TreeNode* des(const char *data, int *len) {
+        if (*len == 0) {
+            return nullptr;
+        }
+
+        int value;
+        const char *s = data + *len - 1;
+        for (int i = 0; i < sizeof(int); i++) {
+            ((char *)&value)[i] = *s--;
+        }
+        if (value == INT_MIN) {
+            (*len) -= sizeof(int);
+            return nullptr;
+        }
+        (*len) -= sizeof(int);
+
+        TreeNode *root = new TreeNode(value);
+        root->right = des(data, len);
+        root->left = des(data, len);
+        return root;
+    }
+};
+
+// Your Codec object will be instantiated and called as such:
+// Codec ser, deser;
+// TreeNode* ans = deser.deserialize(ser.serialize(root));