# Generalized Abbreviation in C++

Suppose there is a word. We have to define a function that can generate the generalized abbreviations of a word.

So, if the input is like "word", then the output will be ["word", "1ord", "w1rd", "wo1d", "wor1", "2rd", "w2d", "wo2", "1o1d", "1or1", "w1r1", "1o2", "2r1", "3d", "w3", "4"]

To solve this, we will follow these steps −

• Define an array ret

• Define a function solve(), this will take s, idx,

• if idx >= size of s, then −

• insert s at the end of ret

• return

• y := substring of s from index 0 to idx - 1

• i := size of y

• num := blank string

• while (i >= 0 and y[i] <= ASCII of '9' and y[i] >= ASCII of '0'), do −

• num := y[i] + num

• (decrease i by 1)

• if i is not equal to size of y, then −

• ret := substring of s from index (0 to idx - (size of y - 1 - i) - 1) concatenate (number + 1)as string concatenate substring of s from index (0 to idx)

• s1 := num + 1 as string

• s2 := num as string

• if size of s1 is same as size of s2, then −

• Otherwise

• solve(ret, idx + 1)

• Otherwise

• prev := s[idx]

• s[idx] := '1'

• solve(s, idx + 1)

• s[idx] := prev

• solve(s, idx + 1)

• From the main method do the following −

• solve(word, 0)

• return ret

## Example

Let us see the following implementation to get better understanding −

Live Demo

#include <bits/stdc++.h>
using namespace std;
void print_vector(vector<auto< v){
cout << "[";
for(int i = 0; i<v.size(); i++){
cout << v[i] << ", ";
}
cout << "]"<<endl;
}
class Solution {
public:
vector<string> ret;
void solve(string s, int idx){
if (idx >= s.size()) {
ret.push_back(s);
return;
}
string y = s.substr(0, idx);
int i = y.size() - 1;
string num = "";
while (i >= 0 && y[i] <= '9' && y[i] >= '0') {
num = y[i] + num;
i--;
}
if (i != y.size() - 1) {
string ret = s.substr(0, idx - (y.size() - 1 - i)) + to_string(stoi(num) + 1) + s.substr(idx + 1);
string s1 = to_string(stoi(num) + 1);
string s2 = to_string(stoi(num));
if (s1.size() == s2.size())
solve(ret, idx);
else
solve(ret, idx + 1);
}
else {
char prev = s[idx];
s[idx] = '1';
solve(s, idx + 1);
s[idx] = prev;
}
solve(s, idx + 1);
}
vector<string< generateAbbreviations(string word){
solve(word, 0);
return ret;
}
};
main(){
Solution ob;
print_vector(ob.generateAbbreviations("hello"));
}

## Input

hello

## Output

[5, 4o, 3l1, 3lo, 2l2, 2l1o, 2ll1, 2llo, 1e3, 1e2o, 1e1l1, 1e1lo, 1el2, 1el1o, 1ell1, 1ello, h4, h3o, h2l1, h2lo, h1l2, h1l1o, h1ll1, h1llo, he3, he2o, he1l1, he1lo, hel2, hel1o, hell1, hello, ]