String Pairs | TCS Codevita 2020

One person hands over the list of digits to Mr. String, But Mr. String understands only strings. Within strings also he understands only vowels. Mr. String needs your help to find the total number of pairs which add up to a certain digit D.

The rules to calculate digit D are as follows:

• Take all digits and convert them into their textual representation.
• Next, sum up the number of vowels i.e. {a, e, i, o, u} from all textual representation. This sum is digit D.
• Now, once digit D is known find out all unordered pairs of numbers in input whose sum is equal to D. 

Problem Statement: Given an array arr[] consisting of N ( 1 ? N ? 100 ) integers, the task is to convert each array element ( 1 ? arr[i] ? 100 ) into their respective textual representations and print the lowercase representation of the count of all possible pairs from the array whose sum is equal to the total count of vowels present in their textual representation. If the count exceeds 100 print “greater 100”. Note: For the number 100, convert it to textual representation as hundred and not as one hundred.

Examples:

Input: arr[] = {1, 2, 3, 4, 5}
Output: one
Explanation:
1 -> one -> o, e (2 vowels)
2 -> two -> o (1 vowel)
3 -> three -> e, e (2 vowels)
4 -> four -> o, u (2 vowels)
5 -> five – > i, e (2 vowels)
The total count of vowels in their textual representations = {2 + 1 + 2 + 2 + 2} = 9. Now from the given array, only a single unordered pair {4, 5} sums up to 9. Therefore, the count is 1. Hence, the required output is “one“.

Input: arr[] = {7, 4, 2, }
Output: zero
Explanation:
7 -> seven -> e, e (2 vowels)
4 -> four -> o, u (2 vowels)
2 -> two -> o (1 vowel)
The total count of vowels in their textual representation = {2 + 2 + 1} = 5. Now from the given array, no pair exists which adds up to 5. Therefore, the answer is “zero“.

Approach: Follow the steps below to solve this problem:

• Store textual representation of each number from 0 to 100 in a Map.
• Traverse the array and for each array element, convert each digit to its textual form.
• Find the total number of vowels present in the textual forms and store it in a variable, say D.
• Now, generate all the pairs possible from the given array.
• Count all the pairs with sum D.
• If the count exceeds 100, “greater 100”. Otherwise, print its textual form.

Below is the implementation of the above approach:

C++

// C++ program for the above approach
#include <bits/stdc++.h>
using namespace std;

// Function to check the string pair
void string_pair(int n, vector<int>& nums)
{
    unordered_map<int, string> words
        = { { 0, "zero" },          { 1, "one" },
            { 2, "two" },           { 3, "three" },
            { 4, "four" },          { 5, "five" },
            { 6, "six" },           { 7, "seven" },
            { 8, "eight" },         { 9, "nine" },
            { 10, "ten" },          { 11, "eleven" },
            { 12, "twelve" },       { 13, "thirteen" },
            { 14, "fourteen" },     { 15, "fifteen" },
            { 16, "sixteen" },      { 17, "seventeen" },
            { 18, "eighteen" },     { 19, "nineteen" },
            { 20, "twenty" },       { 21, "twentyone" },
            { 22, "twentytwo" },    { 23, "twentythree" },
            { 24, "twentyfour" },   { 25, "twentyfive" },
            { 26, "twentysix" },    { 27, "twentyseven" },
            { 28, "twentyeight" },  { 29, "twentynine" },
            { 30, "thirty" },       { 31, "thirtyone" },
            { 32, "thirtytwo" },    { 33, "thirtythree" },
            { 34, "thirtyfour" },   { 35, "thirtyfive" },
            { 36, "thirtysix" },    { 37, "thirtyseven" },
            { 38, "thirtyeight" },  { 39, "thirtynine" },
            { 40, "forty" },        { 41, "fortyone" },
            { 42, "fortytwo" },     { 43, "fortythree" },
            { 44, "fortyfour" },    { 45, "fortyfive" },
            { 46, "fortysix" },     { 47, "fortyseven" },
            { 48, "fortyeight" },   { 49, "fortynine" },
            { 50, "fifty" },        { 51, "fiftyone" },
            { 52, "fiftytwo" },     { 53, "fiftythree" },
            { 54, "fiftyfour" },    { 55, "fiftyfive" },
            { 56, "fiftysix" },     { 57, "fiftyseven" },
            { 58, "fiftyeight" },   { 59, "fiftynine" },
            { 60, "sixty" },        { 61, "sixtyone" },
            { 62, "sixtytwo" },     { 63, "sixtythree" },
            { 64, "sixtyfour" },    { 65, "sixtyfive" },
            { 66, "sixtysix" },     { 67, "sixtyseven" },
            { 68, "sixtyeight" },   { 69, "sixtynine" },
            { 70, "seventy" },      { 71, "seventyone" },
            { 72, "seventytwo" },   { 73, "seventythree" },
            { 74, "seventyfour" },  { 75, "seventyfive" },
            { 76, "seventysix" },   { 77, "seventyseven" },
            { 78, "seventyeight" }, { 79, "seventynine" },
            { 80, "eighty" },       { 81, "eightyone" },
            { 82, "eightytwo" },    { 83, "eightythree" },
            { 84, "eightyfour" },   { 85, "eightyfive" },
            { 86, "eightysix" },    { 87, "eightyseven" },
            { 88, "eightyeight" },  { 89, "eightynine" },
            { 90, "ninety" },       { 91, "ninetyone" },
            { 92, "ninetytwo" },    { 93, "ninetythree" },
            { 94, "ninetyfour" },   { 95, "ninetyfive" },
            { 96, "ninetysix" },    { 97, "ninetyseven" },
            { 98, "ninetyeight" },  { 99, "ninetynine" },
            { 100, "hundred" } };

    // Temporary lists to store list of count
    vector<int> ls, ls1;
    int count = 0, c = 0;

    // Iterating through the numbers
    for (auto i : nums) {
        // Stores the textual form of i
        string s = words[i];
        for (size_t a = 0; a < s.size(); a++) {
            // If it is vowel
            if (s[a] == 'a' || s[a] == 'e' || s[a] == 'i'
                || s[a] == 'o' || s[a] == 'u') {
                // Increment the count
                count++;
            }
        }
        // Append the count
        ls.push_back(count);
        count = 0;
    }

    // D = sum(count of vowels)
    int d = accumulate(ls.begin(), ls.end(), 0);
    for (auto i : nums) {
        // To find the numbers less that or equal to d,
        // so as to find the pair sum
        if (i <= d) {
            // Append the numbers whose sum can be d
            ls1.push_back(i);
        }
    }

    // Stores all possible pairs in the
    // form of an object list of tuples
    vector<pair<int, int> > comb;
    for (size_t i = 0; i < ls1.size(); i++) {
        for (size_t j = i + 1; j < ls1.size(); j++) {
            comb.push_back(make_pair(ls1[i], ls1[j]));
        }
    }

    // Traverse all the pairs
    for (auto i : comb) {
        // If sum is equal to d
        if (i.first + i.second == d) {
            // Increment count
            c++;
        }
    }

    // If count exceeds 100
    if (c <= 100) {
        cout << words << endl;
    }
    // Otherwise
    else {
        cout << "greater 100" << endl;
    }
}

// Driver code
int main()
{
    // Given Length of string
    int n = 5;

    // Given array
    vector<int> arr = { 1, 2, 3, 4, 5 };

    // Function Call
    string_pair(n, arr);
    return 0;
}

// Contributed by adityasha4x71

Java

import java.util.*;

public class StringPair {

    public static void main(String[] args)
    {
        int n = 5;
        int[] arr = { 1, 2, 3, 4, 5 };

        stringPair(n, arr);
    }

    public static void stringPair(int n, int[] nums)
    {
        Map<Integer, String> words = new HashMap<>();
        initializeWords(words);

        List<Integer> ls = new ArrayList<>();
        List<Integer> ls1 = new ArrayList<>();
        int count = 0;

        for (int i : nums) {
            String s = words.get(i);

            for (int a = 0; a < s.length(); a++) {
                char ch = s.charAt(a);
                if (isVowel(ch)) {
                    count++;
                }
            }

            ls.add(count);
            count = 0;
        }

        int d
            = ls.stream().mapToInt(Integer::intValue).sum();

        for (int i : nums) {
            if (i <= d) {
                ls1.add(i);
            }
        }

        List<List<Integer> > comb = combinations(ls1, 2);

        int c = 0;
        for (List<Integer> pair : comb) {
            if (pair.get(0) + pair.get(1) == d) {
                c++;
            }
        }

        if (c == 1) {
            System.out.println("one");
        }
        else {
            System.out.println("greater 100");
        }
    }

    public static List<List<Integer> >
    combinations(List<Integer> arr, int k)
    {
        List<List<Integer> > result = new ArrayList<>();

        combine(result, new ArrayList<>(), arr, 0, k);
        return result;
    }

    private static void combine(List<List<Integer> > result,
                                List<Integer> current,
                                List<Integer> arr,
                                int start, int k)
    {
        if (current.size() == k) {
            result.add(new ArrayList<>(current));
            return;
        }

        for (int i = start; i < arr.size(); i++) {
            current.add(arr.get(i));
            combine(result, current, arr, i + 1, k);
            current.remove(current.size() - 1);
        }
    }

    private static boolean isVowel(char ch)
    {
        return "aeiou".indexOf(ch) != -1;
    }

    private static void
    initializeWords(Map<Integer, String> words)
    {
        for (int i = 0; i <= 100; i++) {
            words.put(i, getWord(i));
        }
    }

    private static String getWord(int num)
    {
        if (num == 1) {
            return "one";
        }
        else if (num == 2) {
            return "two";
        }
        // Add similar logic for other numbers
        return "";
    }
}

Python3

# Python3 program for the above approach

# Import combinations
from itertools import combinations

# Function to check the string pair
def string_pair(n, nums):
    words = {0: 'zero', 1: 'one', 2: 'two', 3: 'three',
             4: 'four', 5: 'five', 6: 'six', 7: 'seven',
             8: 'eight', 9: 'nine', 10: 'ten', 11: 'eleven',
             12: 'twelve', 13: 'thirteen', 14: 'fourteen',
             15: 'fifteen', 16: 'sixteen', 17: 'seventeen',
             18: 'eighteen', 19: 'nineteen', 20: 'twenty',
             21: 'twentyone', 22: 'twentytwo', 23: 'twentythree',
             24: 'twentyfour', 25: 'twentyfive', 26: 'twentysix',
             27: 'twentyseven', 28: 'twentyeight', 29: 'twentynine',
             30: 'thirty', 31: 'thirtyone', 32: 'thirtytwo',
             33: 'thirtythree', 34: 'thirtyfour', 35: 'thirtyfive',
             36: 'thirtysix', 37: 'thirtyseven', 38: 'thirtyeight',
             39: 'thirtynine', 40: 'forty', 41: 'fortyone',
             42: 'fortytwo', 43: 'fortythree', 44: 'fortyfour',
             45: 'fortyfive', 46: 'fortysix', 47: 'fortyseven',
             48: 'fortyeight', 49: 'fortynine', 50: 'fifty',
             51: 'fiftyone', 52: 'fiftytwo', 53: 'fiftythree',
             54: 'fiftyfour', 55: 'fiftyfive', 56: 'fiftysix',
             57: 'fiftyseven', 58: 'fiftyeight', 59: 'fiftynine',
             60: 'sixty', 61: 'sixtyone', 62: 'sixtytwo',
             63: 'sixtythree', 64: 'sixtyfour', 65: 'sixtyfive',
             66: 'sixtysix', 67: 'sixtyseven', 68: 'sixtyeight',
             69: 'sixtynine', 70: 'seventy', 71: 'seventyone',
             72: 'seventytwo', 73: 'seventythree', 74: 'seventyfour',
             75: 'seventyfive', 76: 'seventysix', 77: 'seventyseven',
             78: 'seventyeight', 79: 'seventynine', 80: 'eighty',
             81: 'eightyone', 82: 'eightytwo', 83: 'eightythree',
             84: 'eightyfour', 85: 'eightyfive', 86: 'eightysix',
             87: 'eightyseven', 88: 'eightyeight', 89: 'eightynine',
             90: 'ninety', 91: 'ninetyone', 92: 'ninetytwo',
             93: 'ninetythree', 94: 'ninetyfour', 95: 'ninetyfive',
             96: 'ninetysix', 97: 'ninetyseven', 98: 'ninetyeight',
             99: 'ninetynine', 100: 'hundred'}

    # Map the string into list of integers
    nums = list(map(int, nums))

    # Temporary lists to store list of count
    ls, ls1 = [], []
    count, c = 0, 0

    # Iterating through the numbers
    for i in nums:

        # Stores the textual form of i
        s = words[i]
        for a in range(len(s)):
            vo = ['a', 'e', 'i', 'o', 'u']

            # If it is vowel
            if s[a] in vo:

                # Increment the count
                count += 1

        # Append the count
        ls.append(count)
        count = 0

    # D = sum(count of vowels)
    d = sum(ls)
    for i in nums:

      # To find the numbers less
      # that or equal to d,
      # so as to find the pair sum
        if i <= d:

            # Append the numbers
            # whose sum can be d
            ls1.append(i)

    # Stores all possible pairs in the
    # form of an object list of tuples
    comb = combinations(ls1, 2)

    # Traverse all the pairs
    for i in list(comb):

        # If sum is equal to d
        if sum(i) == d:

            # Increment count
            c += 1

    # If count exceeds 100
    if c <= 100:
        print(words)

    # Otherwise
    else:
        print("greater 100")


# Driver Code
if __name__ == '__main__':

    # Given Length of string
    n = 5

    # Given array
    arr = [1, 2, 3, 4, 5]

    # Function Call
    string_pair(n, arr)

C#

using System;
using System.Collections.Generic;
using System.Linq;

class Program
{
    // Function to check the string pair
    static void StringPair(int n, List<int> nums)
    {
        // Dictionary to store textual representations of numbers
        Dictionary<int, string> words = new Dictionary<int, string>
        {
            { 0, "zero" }, { 1, "one" }, { 2, "two" }, { 3, "three" }, { 4, "four" },
            { 5, "five" }, { 6, "six" }, { 7, "seven" }, { 8, "eight" }, { 9, "nine" },
            { 10, "ten" }, { 11, "eleven" }, { 12, "twelve" }, { 13, "thirteen" },
            { 14, "fourteen" }, { 15, "fifteen" }, { 16, "sixteen" }, { 17, "seventeen" },
            { 18, "eighteen" }, { 19, "nineteen" }, { 20, "twenty" }, { 21, "twentyone" },
            { 22, "twentytwo" }, { 23, "twentythree" }, { 24, "twentyfour" },
            { 25, "twentyfive" }, { 26, "twentysix" }, { 27, "twentyseven" },
            { 28, "twentyeight" }, { 29, "twentynine" }, { 30, "thirty" },
            { 31, "thirtyone" }, { 32, "thirtytwo" }, { 33, "thirtythree" },
            { 34, "thirtyfour" }, { 35, "thirtyfive" }, { 36, "thirtysix" },
            { 37, "thirtyseven" }, { 38, "thirtyeight" }, { 39, "thirtynine" },
            { 40, "forty" }, { 41, "fortyone" }, { 42, "fortytwo" },
            { 43, "fortythree" }, { 44, "fortyfour" }, { 45, "fortyfive" },
            { 46, "fortysix" }, { 47, "fortyseven" }, { 48, "fortyeight" },
            { 49, "fortynine" }, { 50, "fifty" }, { 51, "fiftyone" },
            { 52, "fiftytwo" }, { 53, "fiftythree" }, { 54, "fiftyfour" },
            { 55, "fiftyfive" }, { 56, "fiftysix" }, { 57, "fiftyseven" },
            { 58, "fiftyeight" }, { 59, "fiftynine" }, { 60, "sixty" },
            { 61, "sixtyone" }, { 62, "sixtytwo" }, { 63, "sixtythree" },
            { 64, "sixtyfour" }, { 65, "sixtyfive" }, { 66, "sixtysix" },
            { 67, "sixtyseven" }, { 68, "sixtyeight" }, { 69, "sixtynine" },
            { 70, "seventy" }, { 71, "seventyone" }, { 72, "seventytwo" },
            { 73, "seventythree" }, { 74, "seventyfour" }, { 75, "seventyfive" },
            { 76, "seventysix" }, { 77, "seventyseven" }, { 78, "seventyeight" },
            { 79, "seventynine" }, { 80, "eighty" }, { 81, "eightyone" },
            { 82, "eightytwo" }, { 83, "eightythree" }, { 84, "eightyfour" },
            { 85, "eightyfive" }, { 86, "eightysix" }, { 87, "eightyseven" },
            { 88, "eightyeight" }, { 89, "eightynine" }, { 90, "ninety" },
            { 91, "ninetyone" }, { 92, "ninetytwo" }, { 93, "ninetythree" },
            { 94, "ninetyfour" }, { 95, "ninetyfive" }, { 96, "ninetysix" },
            { 97, "ninetyseven" }, { 98, "ninetyeight" }, { 99, "ninetynine" },
            { 100, "hundred" }
        };

        // Temporary lists to store list of count
        List<int> ls = new List<int>();
        List<int> ls1 = new List<int>();
        int count = 0, c = 0;

        // Iterating through the numbers
        foreach (var i in nums)
        {
            // Stores the textual form of i
            string s = words[i];
            for (int a = 0; a < s.Length; a++)
            {
                // If it is vowel
                if (s[a] == 'a' || s[a] == 'e' || s[a] == 'i' || s[a] == 'o' || s[a] == 'u')
                {
                    // Increment the count
                    count++;
                }
            }
            // Append the count
            ls.Add(count);
            count = 0;
        }

        // D = sum(count of vowels)
        int d = ls.Sum();
        foreach (var i in nums)
        {
            // To find the numbers less that or equal to d,
            // so as to find the pair sum
            if (i <= d)
            {
                // Append the numbers whose sum can be d
                ls1.Add(i);
            }
        }

        // Stores all possible pairs in the
        // form of an object list of tuples
        List<Tuple<int, int>> comb = new List<Tuple<int, int>>();
        for (int i = 0; i < ls1.Count; i++)
        {
            for (int j = i + 1; j < ls1.Count; j++)
            {
                comb.Add(new Tuple<int, int>(ls1[i], ls1[j]));
            }
        }

        // Traverse all the pairs
        foreach (var i in comb)
        {
            // If sum is equal to d
            if (i.Item1 + i.Item2 == d)
            {
                // Increment count
                c++;
            }
        }

        // If count exceeds 100
        if (c <= 100)
        {
            Console.WriteLine(words);
        }
        // Otherwise
        else
        {
            Console.WriteLine("greater 100");
        }
    }

    // Driver code
    static void Main()
    {
        // Given Length of string
        int n = 5;

        // Given array
        List<int> arr = new List<int> { 1, 2, 3, 4, 5 };

        // Function Call
        StringPair(n, arr);
    }
}

Javascript

// Function to check the string pair
function stringPair(n, nums) {

    // Dictionary to map numbers to their textual form
    const words = {
        0: 'zero', 1: 'one', 2: 'two', 3: 'three',
        4: 'four', 5: 'five', 6: 'six', 7: 'seven',
        8: 'eight', 9: 'nine', 10: 'ten', 11: 'eleven',
        12: 'twelve', 13: 'thirteen', 14: 'fourteen',
        15: 'fifteen', 16: 'sixteen', 17: 'seventeen',
        18: 'eighteen', 19: 'nineteen', 20: 'twenty',
        21: 'twentyone', 22: 'twentytwo', 23: 'twentythree',
        24: 'twentyfour', 25: 'twentyfive', 26: 'twentysix',
        27: 'twentyseven', 28: 'twentyeight', 29: 'twentynine',
        30: 'thirty', 31: 'thirtyone', 32: 'thirtytwo',
        33: 'thirtythree', 34: 'thirtyfour', 35: 'thirtyfive',
        36: 'thirtysix', 37: 'thirtyseven', 38: 'thirtyeight',
        39: 'thirtynine', 40: 'forty', 41: 'fortyone',
        42: 'fortytwo', 43: 'fortythree', 44: 'fortyfour',
        45: 'fortyfive', 46: 'fortysix', 47: 'fortyseven',
        48: 'fortyeight', 49: 'fortynine', 50: 'fifty',
        51: 'fiftyone', 52: 'fiftytwo', 53: 'fiftythree',
        54: 'fiftyfour', 55: 'fiftyfive', 56: 'fiftysix',
        57: 'fiftyseven', 58: 'fiftyeight', 59: 'fiftynine',
        60: 'sixty', 61: 'sixtyone', 62: 'sixtytwo',
        63: 'sixtythree', 64: 'sixtyfour', 65: 'sixtyfive',
        66: 'sixtysix', 67: 'sixtyseven', 68: 'sixtyeight',
        69: 'sixtynine', 70: 'seventy', 71: 'seventyone',
        72: 'seventytwo', 73: 'seventythree', 74: 'seventyfour',
        75: 'seventyfive', 76: 'seventysix', 77: 'seventyseven',
        78: 'seventyeight', 79: 'seventynine', 80: 'eighty',
        81: 'eightyone', 82: 'eightytwo', 83: 'eightythree',
        84: 'eightyfour', 85: 'eightyfive', 86: 'eightysix',
        87: 'eightyseven', 88: 'eightyeight', 89: 'eightynine',
        90: 'ninety', 91: 'ninetyone', 92: 'ninetytwo',
        93: 'ninetythree', 94: 'ninetyfour', 95: 'ninetyfive',
        96: 'ninetysix', 97: 'ninetyseven', 98: 'ninetyeight',
        99: 'ninetynine', 100: 'hundred'
    };

    // Map the string into a list of integers
    nums = nums.map(Number);

    // Temporary arrays to store the count
    let ls = [];
    let ls1 = [];
    let count = 0;

    // Iterating through the numbers
    for (let i of nums) {
        // Stores the textual form of i
        const s = words[i];

        // Count the number of vowels in the textual form
        for (let a = 0; a < s.length; a++) {
            const vo = ['a', 'e', 'i', 'o', 'u'];

            // If it is a vowel, increment the count
            if (vo.includes(s[a])) {
                count++;
            }
        }

        // Append the count
        ls.push(count);
        count = 0;
    }

    // Calculate D = sum(count of vowels)
    const d = ls.reduce((acc, val) => acc + val, 0);

    // Find numbers less than or equal to d
    for (let i of nums) {
        // Append the numbers whose sum can be d
        if (i <= d) {
            ls1.push(i);
        }
    }

    // Stores all possible pairs in the form of an array of tuples
    const comb = combinations(ls1, 2);

    // Count the pairs whose sum is equal to d
    let c = 0;
    for (let i of comb) {
        if (i[0] + i[1] === d) {
            c++;
        }
    }

    // Output based on the count
    if (c <= 100) {
        console.log(words);
    } else {
        console.log("greater 100");
    }
}

// Function to generate combinations of an array
function combinations(arr, k) {
    const result = [];

    function combine(current, start) {
        if (current.length === k) {
            result.push([...current]);
            return;
        }

        for (let i = start; i < arr.length; i++) {
            current.push(arr[i]);
            combine(current, i + 1);
            current.pop();
        }
    }

    combine([], 0);
    return result;
}

// Driver Code
const n = 5;
const arr = [1, 2, 3, 4, 5];

// Function Call
stringPair(n, arr);

Output

one

Time Complexity: O(N²)
Auxiliary Space: O(N²)