#include <bits/stdc++.h>
using namespace std;

// tree node structure
struct Node {
    int data;
    Node *left;
    Node *right;

    Node (int data) {
        this -> data = data;
        this -> left = NULL;
        this -> right = NULL;
    }
};

Node *buildTree(int idx, vector<int> &tree) {

    if(idx > tree.size() || tree[idx] == 0) {
        return NULL;
    }

    // create current node
    Node *curr = new Node(tree[idx]);

    // recursive calls for left and right subtree
    curr  -> left = buildTree(2 * idx + 1, tree);
    curr -> right = buildTree(2 * idx + 2, tree);

    return curr;

}

void inorderTraversal(Node *root, vector<int> &inorder) {

    if(root == NULL) {
        return;
    }

    inorderTraversal(root -> left, inorder);
    inorder.push_back(root -> data);
    inorderTraversal(root -> right, inorder);

}

int main() {
    
    int N; 
    cin >> N;

    vector<int> tree(N);

    for(int i = 0; i < N; i++) {
        cin >> tree[i];
    }
    
    // build the binary search tree
    Node *root = buildTree(0, tree);
    
    // get the inorder traversal of the given tree
    vector<int> inorder;
    inorderTraversal(root, inorder);
    
    // sort the values in the given tree
    sort(tree.begin(), tree.end());
    
    vector<int> ans;
    int idx1 = 0, idx2 = 0;
    
    
    // compare sorted tree and inorder traversal
    while(idx1 < tree.size() && idx2 < inorder.size()) {
        if(tree[idx1] == 0) {
            idx1++;
            continue;
        }
        if(tree[idx1] != inorder[idx2]) {
            // print the result
            cout << min(tree[idx1], inorder[idx2]) << " " << max(tree[idx1], inorder[idx2]) << endl;
            break;
        }
        idx1++; idx2++;
    }

    return 0;
}

C++ Online Compiler

Write, Run & Share C++ code online using OneCompiler's C++ online compiler for free. It's one of the robust, feature-rich online compilers for C++ language, running on the latest version 17. Getting started with the OneCompiler's C++ compiler is simple and pretty fast. The editor shows sample boilerplate code when you choose language as C++ and start coding!

Read inputs from stdin

OneCompiler's C++ online compiler supports stdin and users can give inputs to programs using the STDIN textbox under the I/O tab. Following is a sample program which takes name as input and print your name with hello.

#include <iostream>
#include <string>
using namespace std;

int main() 
{
    string name;
    cout << "Enter name:";
    getline (cin, name);
    cout << "Hello " << name;
    return 0;
}

About C++

C++ is a widely used middle-level programming language.

  • Supports different platforms like Windows, various Linux flavours, MacOS etc
  • C++ supports OOPS concepts like Inheritance, Polymorphism, Encapsulation and Abstraction.
  • Case-sensitive
  • C++ is a compiler based language
  • C++ supports structured programming language
  • C++ provides alot of inbuilt functions and also supports dynamic memory allocation.
  • Like C, C++ also allows you to play with memory using Pointers.

Syntax help

Loops

1. If-Else:

When ever you want to perform a set of operations based on a condition If-Else is used.

if(conditional-expression) {
   //code
}
else {
   //code
}

You can also use if-else for nested Ifs and If-Else-If ladder when multiple conditions are to be performed on a single variable.

2. Switch:

Switch is an alternative to If-Else-If ladder.

switch(conditional-expression){    
case value1:    
 // code    
 break;  // optional  
case value2:    
 // code    
 break;  // optional  
......    
    
default:     
 code to be executed when all the above cases are not matched;    
}

3. For:

For loop is used to iterate a set of statements based on a condition.

for(Initialization; Condition; Increment/decrement){  
  //code  
}

4. While:

While is also used to iterate a set of statements based on a condition. Usually while is preferred when number of iterations are not known in advance.

while (condition) {  
// code 
}

5. Do-While:

Do-while is also used to iterate a set of statements based on a condition. It is mostly used when you need to execute the statements atleast once.

do {  
 // code 
} while (condition);

Functions

Function is a sub-routine which contains set of statements. Usually functions are written when multiple calls are required to same set of statements which increases re-usuability and modularity. Function gets run only when it is called.

How to declare a Function:

return_type function_name(parameters);

How to call a Function:

function_name (parameters)

How to define a Function:

return_type function_name(parameters) {  
 // code
}