Contacts

                            Solution in C :

In C ++ :





#include <bits/stdc++.h>
using namespace std;
struct node{
    int h[26],n,f;
};
node null;
vector<node>trie;
void add(string &A){
    int i,j,p,q,act=0;
    for(i=0;i<A.size();i++){
        p=A[i]-'a';
        if(!trie[act].h[p]){
            trie[act].h[p]=trie.size();
            trie.push_back(null);
        }
        act=trie[act].h[p];
        trie[act].n++;
    }
}
int findi(string &A){
    int i,j,p,q,act=0;
    for(i=0;i<A.size();i++){
        p=A[i]-'a';
        if(!trie[act].h[p])return 0;
        act=trie[act].h[p];
    }
    return trie[act].n;
}
int main(){
    int i,j,p,q,N;
    string A,B;
    null.n=null.f=0;
    for(i=0;i<26;i++)null.h[i]=0;
    trie.push_back(null);
    cin>>N;
    for(i=0;i<N;i++){
        cin>>A>>B;
        if(A=="add")add(B);
        else cout<<findi(B)<<"\n";
    }
}








In Java :





import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;


class TrieNode{
    int count = 0;
    TrieNode[] trieNode = new TrieNode[26];
}


class Trie{
    TrieNode contacts = new TrieNode();
    
    public void add(String contact){
        
        TrieNode temp = contacts;
        temp.count++;
        
        for(char c : contact.toCharArray()){
            
            int index = c - 'a';
            if(temp.trieNode[index] != null){
                temp = temp.trieNode[index];
            }
            else{
                temp.trieNode[index] = new TrieNode();
                temp = temp.trieNode[index];
            }
            temp.count++; 
        }
        
    }
    
    public int find(String contact){
        
        TrieNode temp = contacts;
        
        for(char c : contact.toCharArray()){
            
            int index = c -'a';
            if(temp.trieNode[index]!=null){
                temp = temp.trieNode[index];
            }
            else{
                return 0;
            }
            
        }
        return temp.count;
    }
}

public class Solution {

    public static void main(String[] args) {
        /* Enter your code here. Read input from STDIN. Print output to STDOUT. Your class should be named Solution. */
        int numContacts;
        Scanner in = new Scanner(System.in);
        int numOperations = in.nextInt();
        
        Trie trie = new Trie();
        
        for(int i = 0; i <= numOperations; i++){
            String op = in.nextLine();
            
            String spl[] = op.split(" ");
            
            //System.out.println("Input:"+op);
            if(spl[0].equals("add")){
                //System.out.println("Adding"+spl[1]);
                trie.add(spl[1]);
            }
            if(spl[0].equals("find")){
                //System.out.println("finding"+spl[1]);
                numContacts = trie.find(spl[1]);
                System.out.println(numContacts);
            }
        }
    }
}








In C :




#include <stdio.h>
#include <string.h>
#include <math.h>
#include <stdlib.h>
#include <stdbool.h>
typedef struct node
{
    bool isEOW;
    int count;
    struct node *letters[26];
} Trie;
Trie *createNode()
{
    int i;
    Trie *temp=malloc(sizeof(Trie));
    temp->isEOW=false;
    temp->count=0;
    for(i=0; i<26; i++)
    {
        temp->letters[i]=NULL;
    }
    return temp;
}
Trie *insert(Trie *root,char *name)
{
    int i;
    Trie *temp=root;
    for(i=0; name[i]!='\0'; i++)
    {
        if(root->letters[name[i]-'a']==NULL)
            root->letters[name[i]-'a']=createNode();
        root=root->letters[name[i]-'a'];
        root->count++;
    }
    root->isEOW=true;
    return temp;
}
/*int countNames(Trie *root)
{
    int i,count=0;
    if(root->isEOW)
        count++;
    for(i=0; i<26; i++)
    {
        if(root->letters[i])
            count=count+countNames(root->letters[i]);
    }
    return count;
}*/
int main()
{

    int i;
    long n;
    Trie* root=createNode();
    scanf("%ld",&n);
    char a[5],name[22];
    while(n--)
    {
        scanf("%s",a);
        scanf(" %s",name);
        if(strcmp(a,"add")==0)
            root= insert(root,name);
        else if(strcmp(a,"find")==0)
        {
            Trie *temp=root;
            for(i=0; i<strlen(name); i++)
            {
                temp=temp->letters[name[i]-'a'];
                if(!temp)
                {
                    printf("0\n");
                    break;
                }
            }
            if(i==strlen(name))
                printf("%d\n",temp->count);
        }
    }
    return 0;
}








In Python3 :




N = int(input())

trie = {}

def add_word(trie, word):
    # Base case
    if word == "": return
    
    # TODO: default dict
    if word[0] in trie:
        trie[word[0]]['count'] += 1
    else:
        trie[word[0]] = { 'count': 1 }
    add_word(trie[word[0]], word[1:])
    
def find_word(trie, word):
    if word[0] not in trie:
        return 0
    else:
        # Base case
        if len(word) == 1:
            return trie[word[0]]['count']
        else:
            return find_word(trie[word[0]], word[1:])

for i in range(N):
    line = input()
    command, word = line.split()
    if command == "add":
        add_word(trie, word)
    elif command == "find":
        print(find_word(trie, word))
    else:
        print("WTF")