« Print keypad combinations code

Problem

Given an integer n, using phone keypad find out and print all the possible strings that can be made using digits of input n.

Note : The order of strings are not important. Just print different strings in new lines.

Input Format :

Integer n

Output Format :

All possible strings in different lines

Constraints :

1 <= n <= 10^6

Sample Input:

23

Sample Output:

ad

ae

af

bd

be

bf

cd

ce

cf

Solution

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1#include <iostream>
2#include <iomanip>
3#include <algorithm>
4#include <string>
5#include <cstring>
6#include <vector>
7#include <cmath>
8#include <map>
9#include <climits>
10// climits for INT_MIN
11#include <unordered_map>
12using namespace std;
13
14string dial(int key)
15{
16    unordered_map<int, string> m;
17    m[0] = "";
18    m[1] = "";
19    m[2] = "abc";
20    m[3] = "def";
21    m[4] = "ghi";
22    m[5] = "jkl";
23    m[6] = "mno";
24    m[7] = "pqrs";
25    m[8] = "tuv";
26    m[9] = "wxyz";
27    return m[key];
28}
29
30void printKeypad(int num, string out)
31{
32    if (num == 0)
33    {
34        cout << out << endl;
35        return;
36    }
37    string str = dial(num % 10);
38    for (int i = 0; i < str.size(); i++)
39    {
40        printKeypad(num / 10, str[i] + out);
41    }
42}
43
44void printKeypad(int num)
45{
46    printKeypad(num, "");
47}
48
49int main()
50{
51    int num;
52    cin >> num;
53    printKeypad(num);
54    return 0;
55}