Search a string in the dictionary with a given prefix and suffix for Q queries

// C# Program for the above approach
using System;
using System.Collections.Generic;

class Program
{
    static void Main(string[] args)
    {
        // N is the number of strings in the array
        int N = 8;

        // Declare an array of size N
        string[] arr = { "apple", "app", "biscuit", "mouse", "orange", "bat", "mine", "mine" };

        List<List<string>> Q = new List<List<string>> { new List<string> { "a", "e" }, new List<string> { "mi", "ne" } };

        // Taking input the queries 
        string prefix, suffix;
        for (int i = 0; i < Q.Count; i++)
        {
            prefix = Q[i][0];
            suffix = Q[i][1];

            // Flag to check if string is found 
            // with given prefix and suffix
            int found = 0;

            // Check every string in arr[]
            for (int j = 0; j < N; j++)
            {
                // If string is found with given 
                // prefix and suffix
                if (arr[j].IndexOf(prefix) == 0 && arr[j].LastIndexOf(suffix) == arr[j].Length - suffix.Length)
                {
                    // Print the string
                    Console.WriteLine(arr[j]);

                    // Set flag to 1 to indicate that 
                    // string is found
                    found = 1;
                    break;
                }
            }
            if (found == 0)
                Console.WriteLine("-1");
        }
    }
}

// Contributed by rishabmalhdijo

// C# program for the above approach
using System;
class GFG {

  // Trie Node
  public class Trie {
    public Trie[] arr = new Trie[27];

    // Stores the index of the word
    // in the dictionary
    public int idx;
  };

  // Root node of the Trie
  public static Trie root;

  // Function to insert the words in
  // the Trie
  public static void insert(String word, int i)
  {
    // Temporary pointer to the root
    // node of the Trie
    Trie temp = root;

    // Traverse through all the
    // characters of current word
    for (int ch = 0; ch < word.Length; ch++) {

      // Make a Trie Node, if not
      // already present
      if (temp.arr[word[ch] - 'a'] == null) {
        Trie t = new Trie();
        temp.arr[word[ch] - 'a'] = t;
      }

      temp = temp.arr[word[ch] - 'a'];
      temp.idx = i;
    }
  }

  // Function to search the words in Trie
  public static int search(String word)
  {
    Trie temp = root;

    // Traverse through all the
    // characters of current word
    for (int ch = 0; ch < word.Length; ch++) {

      // If no valid Trie Node exists
      // for the current character
      // then there is no match
      if (temp.arr[word[ch] - 'a'] == null)
        return -1;
      temp = temp.arr[word[ch] - 'a'];
    }

    // Return the resultant index
    return temp.idx;
  }

  // Function to search for a word in
  // the dictionary with the given
  // prefix and suffix for each query
  public static void
    findMatchingString(String[] words, int n, String[][] Q)
  {
    String temp, t = "";

    // Insertion in the Trie
    for (int i = 0; i < n; i++) {

      // Form all the words of the
      // form suffix{word and insert
      // them in the trie
      temp = "{" + words[i];
      for (int j = words[i].Length - 1; j >= 0; j--) {
        t = words[i][j] + temp;
        temp = t;

        // Insert into Trie
        insert(t, i);
      }
    }

    // Traverse all the queries
    for (int i = 0; i < Q.Length; i++) {
      String prefix = Q[i][0];
      String suffix = Q[i][1];
      temp = suffix + "{" + prefix;

      // Stores the index of
      // the required word
      int res;

      // Store the index of the
      // word in the dictionary
      res = search(temp);

      // In case of match, print
      // the corresponding string
      if (res != -1) {
        Console.WriteLine(words[res]);
      }

      // Otherwise, No match found
      else
        Console.WriteLine("-1");
    }
  }

  public static void Main(String[] args)
  {
    String[] arr
      = { "apple",  "app", "biscuit",    "mouse",
         "orange", "bat", "microphone", "mine" };
    int N = 8;
    root = new Trie();
    String[][] Q = { new String[] { "a", "e" },
                    new String[] { "mi", "ne" } };
    findMatchingString(arr, N, Q);
  }
}

// This code is contributed by ishankhandelwals.