leetcode

Solution to some Leetcode problems written in C++
git clone git://git.dimitrijedobrota.com/leetcode.git
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0101.cpp (797B)

      1 class Solution {
      2     string preorder(TreeNode *root, bool left) {
      3         if (!root) return "";
      4 
      5         string res;
      6         stack<TreeNode *> st;
      7         st.push(root);
      8         while (!st.empty()) {
      9             TreeNode *root = st.top();
     10             st.pop();
     11             if (!root) {
     12                 res += "-";
     13                 continue;
     14             }
     15             res += root->val;
     16             if (left) {
     17                 st.push(root->right);
     18                 st.push(root->left);
     19             } else {
     20                 st.push(root->left);
     21                 st.push(root->right);
     22             }
     23         }
     24         return res;
     25     }
     26 
     27   public:
     28     bool isSymmetric(TreeNode *root) {
     29         if (!root) return false;
     30 
     31         return preorder(root->left, true) == preorder(root->right, false);
     32     }
     33 };