Truncate Sentence

A sentence is a list of words that are separated by a single space with no leading or trailing spaces. Each of the words consists of only uppercase and lowercase English letters (no punctuation).

• For example, "Hello World", "HELLO", and "hello world hello world" are all sentences.

You are given a sentence s​​​​​​ and an integer k​​​​​​. You want to truncate s​​​​​​ such that it contains only the first k​​​​​​ words. Return s​​​​​​ after truncating it.

Example 1:

Input: s = "Hello how are you Contestant", k = 4
Output: "Hello how are you"
Explanation:
The words in s are ["Hello", "how" "are", "you", "Contestant"].
The first 4 words are ["Hello", "how", "are", "you"].
Hence, you should return "Hello how are you".

Example 2:

Input: s = "What is the solution to this problem", k = 4
Output: "What is the solution"
Explanation:
The words in s are ["What", "is" "the", "solution", "to", "this", "problem"].
The first 4 words are ["What", "is", "the", "solution"].
Hence, you should return "What is the solution".

Example 3:

Input: s = "chopper is not a tanuki", k = 5
Output: "chopper is not a tanuki"

Approach

C++

#include <bits/stdc++.h>
using namespace std;

string truncateSentence(string s, int k)
{

    int n = s.size();
    string res = "";
    int i = 0;
    while (i < n)
    {
        string str = "";
        while (i < n && s[i] == ' ')
            i++;
        while (i < n && s[i] != ' ')
        {
            str += s[i];
            i++;
        }
        res += str;
        k--;
        if (k != 0)
            res += " ";
        else
            break;
    }
    return res;
}

int main()
{
    string s = "Hello how are you Contestant";
    int k = 4;

    cout << truncateSentence(s, k) << "\n";

    return 0;
}