106

Author: Ashish-kumar7

106.cpp

@@ -0,0 +1,42 @@
+class Solution {
+public:
+    TreeNode* buildTree(vector<int>& postorder, vector<int>& inorder) {
+        int ins=0;
+        int ine=inorder.size()-1;
+        int posts=0;
+        int poste=postorder.size()-1;
+        return treehelper(postorder,inorder,ins,ine,posts,poste);  
+    }
+    TreeNode * treehelper(vector<int>in,vector<int>pos, int inS, int inE , int posS, int posE){
+    if(inS >inE){
+        return NULL;
+    }
+    int rootdata=pos[posE];
+    int rootindex;
+    for(int i=inS;i<=inE;i++){
+        if(in[i]==rootdata){
+            rootindex=i;
+            break;
+        }
+    }
+    int rootindex1;
+    for(int j=posS;j<=posE;j++){
+        if(pos[j]==rootdata){
+            rootindex1=j;
+            break;
+        }
+    } 
+    int LinS=inS;
+    int LinE=rootindex-1;
+    int LposS=posS;
+    int LposE=LinE-LinS+LposS;
+    int RinS=rootindex+1;
+    int RinE=inE;
+    int RposS=LposE+1;
+    int RposE=rootindex1-1;
+  TreeNode * node1= new TreeNode(rootdata);
+  node1->left=treehelper(in,pos,LinS,LinE,LposS,LposE);
+  node1->right=treehelper(in,pos,RinS,RinE,RposS,RposE);
+   return node1; 
+}
+};