Create Construct Binary Tree from Inorder and Postorder Traversal.cpp

Author: daizhenyang

Construct Binary Tree from Inorder and Postorder Traversal.cpp

@@ -0,0 +1,32 @@
+/**
+ * Definition for binary tree
+ * struct TreeNode {
+ *     int val;
+ *     TreeNode *left;
+ *     TreeNode *right;
+ *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
+ * };
+ */
+class Solution {
+public:
+TreeNode *buildTree(vector<int> &postorder, vector<int> &inorder,int l1,int r1,int l2,int r2) {
+        // Start typing your C/C++ solution below
+        // DO NOT write int main() function
+        if (l1>r1||l2>r2||r1>=postorder.size()||r2>=inorder.size())return NULL;
+        TreeNode *p=new TreeNode(postorder[r1]);
+        int i;
+        for (i=l2;i<=r2;i++)
+        {
+            if (inorder[i]==postorder[r1])break;
+        }
+        p->left=buildTree(postorder,inorder,l1,l1+i-l2-1,l2,i-1);
+        p->right=buildTree(postorder,inorder,l1+i-l2,r1-1,i+1,r2);
+        return p;
+    }
+    TreeNode *buildTree(vector<int> &inorder, vector<int> &postorder) {
+        // Start typing your C/C++ solution below
+        // DO NOT write int main() function
+        if (inorder.empty())return NULL;
+        return buildTree(postorder,inorder,0,postorder.size()-1,0,inorder.size()-1);
+    }
+};