Выпуск#38: ITренировка — актуальные вопросы и задачи от ведущих компаний

#include<bits/stdc++.h>
typedef long long int ll;
using namespace std;

int main()
{
    int t; cin>>t;
    while(t--)
    {
        int n,a,b; cin>>n;
        
        a= (n&15)<<4;
        b= (n&(~15))>>4;
        
        int res=a|b;
        
        cout<<res<<endl;
    }
    return 0;
}

#include <stdio.h>

int main() {
    int t,i,j,n;
    scanf("%d",&t);
    while(t--)
    { int d;
        scanf("%d %d",&n,&d);
        int a[n],count=0;
        for(i=0;i<n;i++)
        {
            scanf("%d",&a[i]);
        }
        for(i=0;i<n-1;i++)
        {
        
            for(j=i+1;j<n;j++)
            {
                if(a[i]+a[j]==d)
                count=count+1;
            }
    
        }
        printf("%d\n",count);
    }
    return 0;

}

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

class Node
{
    public:
    char key;
    bool isTerminating;
    Node(char ch){key=ch; isTerminating=false;}
    std::vector<Node*> children;
};
Node* Root=NULL;

void insertNode(Node* Root, string input)
{
    //first we found the node at which we need to insert if substring of the input is alreadu present we skip
    int index=-1;
    for(int i=0; i<input.size(); i++)
    {
        bool isFound=false;
        for(int j=0; j<Root->children.size(); j++)
        {
            if(!isFound && input[i]==Root->children[j]->key)
            {
                isFound=true; Root=Root->children[j]; index=i;
            }
        }
        //aslong the character is present is the trie we dont break and we skip the character 
        if(!isFound) break;

    }
    
    //after skipping the existing elements we have now reached the node at which we need to insert the string which is left
    //now we can just insert whatever is leftout and mark last node as Terminating
    for(int i=index+1; i<input.size(); i++)
    {
        Node* newNode= new Node(input[i]);
        Root->children.push_back(newNode);
        Root=newNode; Root->isTerminating=false;
    }Root->isTerminating=true;
}

bool searchString(Node* Root, string input)
{
    //searching is similar to insert we keep checking if characters are present and last character is Terminating  
    for(int i=0; i<input.size(); i++)
    {
        bool isFound=false;
        for(int j=0; j<Root->children.size(); j++)
        {
            if(!isFound && Root->children[j]->key==input[i]) 
            {
                isFound=true;
                Root=Root->children[j];
            }
        }
        if(!isFound) return false;
    }
    if(Root->isTerminating) return true;
    return false;
}

void doDFS(Node* Root, string path="")
{
    if(Root->isTerminating) cout<<"Word present is "<<path<<endl;

    for(int i=0; i<Root->children.size(); i++)
    {
        doDFS(Root->children[i], path+Root->children[i]->key);
    }
}

int main()
{

    int t, n;
    cin>>t;

    while(t--)
    {
        cin>>n;
        
        std::vector<string> array;
        string temp;
        for(int i=0; i<n; i++) {cin>>temp; array.push_back(temp);}
        cin>>temp;

        Root=new Node('-');
        Node* tempNode=Root;

        for(int i=0; i<array.size(); i++)
        {
            tempNode=Root;
            insertNode(tempNode, array[i]);
        }
        //uncomment to see the words present in the trie
        //tempNode=Root;
        //doDFS(tempNode);

        tempNode=Root;
        cout<<searchString(tempNode, temp)<<endl;
    }
}