feat:add Solution.cpp for 0106.Construct Binary Tree from Inorder and Postorder Traversal

Author: Stackingrule

solution/0100-0199/0106.Construct Binary Tree from Inorder and Postorder Traversal/Solution.cpp

@@ -0,0 +1,18 @@
+class Solution {
+public:
+    TreeNode *buildTree(vector<int> &inorder, vector<int> &postorder) {
+        return buildTree(inorder, 0, inorder.size() - 1, postorder, 0, postorder.size() - 1);
+    }
+    TreeNode *buildTree(vector<int> &inorder, int iLeft, int iRight, vector<int> &postorder, int pLeft, int pRight) {
+        if (iLeft > iRight || pLeft > pRight) return NULL;
+        TreeNode *cur = new TreeNode(postorder[pRight]);
+        int i = 0;
+        for (i = iLeft; i < inorder.size(); ++i) {
+            if (inorder[i] == cur->val)
+                break;
+        }
+        cur->left = buildTree(inorder, iLeft, i - 1, postorder, pLeft, pLeft + i - iLeft - 1);
+        cur->right = buildTree(inorder, i + 1, iRight, postorder, pLeft + i - iLeft, pRight - 1);
+        return cur;
+    }
+};