Problem:
Provided Inorder and PreOrder of a tree. Construct the tree and print it in PostOrder traversal.
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#include <stdio.h> #include <iostream> #include <string.h> #include<stdlib.h> #include <string> using namespace std; int preOrderIdx=0; struct Node{ int data; Node *left; Node *rit; }; int search(int in[],int in_stIndex,int in_endIndex,int data) { for(int i=in_stIndex;i<=in_endIndex;i++) { if(in[i]==data) return i; } } Node* buildTree(int in[],int pre[],int in_stIndex,int in_endIndex) { //static int preOrderIdx=0; if(in_stIndex>in_endIndex) return NULL; Node *tNode = new Node(); tNode->data=pre[preOrderIdx++]; tNode->left=NULL; tNode->rit=NULL; if(in_stIndex==in_endIndex) return tNode; int rootIndex = search(in,in_stIndex,in_endIndex,tNode->data); tNode->left=buildTree(in,pre,in_stIndex,rootIndex-1); tNode->rit=buildTree(in,pre,rootIndex+1,in_endIndex); return tNode; } void pintPostOrder(Node* res) { Node *tmp; if(res!=NULL) { if(res->left) pintPostOrder(res->left); if(res->rit) pintPostOrder(res->rit); cout<<res->data<<" "; } } int main() { int in[105]; int pre[105]; int t,n; scanf("%d",&t); Node *res,*tmp; while(t--) { scanf("%d",&n); for(int i=0;i<n;i++) scanf("%d",&in[i]); for(int i=0;i<n;i++) scanf("%d",&pre[i]); res=buildTree(in,pre,0,n-1); pintPostOrder(res); } return 0; } |
The problem was provided as a functional problem in Microsoft interview as here [Courtesy : geeksforgeeks]
Solution:
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/* Please note that it's Function problem i.e. you need to write your solution in the form Function(s) only. Driver Code to call/invoke your function would be added by GfG's Online Judge.*/ /*Complete the code here. Node is as follows: struct Node { int data; Node* left; Node* right; }; */ int search(int in[],int in_stIndex,int in_endIndex,int data) { for(int i=in_stIndex;i<=in_endIndex;i++) { if(in[i]==data) return i; } } Node* newbuildTree(int in[],int pre[], int inStrt, int inEnd,int *preOrderIdx) { if(inStrt>inEnd) return NULL; Node *tNode = new Node(); tNode->data=pre[(*preOrderIdx)++]; tNode->left=NULL; tNode->right=NULL; if(inStrt==inEnd) return tNode; int rootIndex = search(in,inStrt,inEnd,tNode->data); tNode->left=newbuildTree(in,pre,inStrt,rootIndex-1,preOrderIdx); tNode->right=newbuildTree(in,pre,rootIndex+1,inEnd,preOrderIdx); return tNode; } Node* buildTree(int in[],int pre[], int inStrt, int inEnd) { //add code here. int preOrderIdx=0; newbuildTree(in,pre, inStrt,inEnd,&preOrderIdx); } |