There is a forum that has a limit of K characters per entry. In this task your job is to implement an algorithm for cropping messages that are too long. You are given a message, consisting of English alphabet letters and spaces, that might be longer than the limit. Your algorithm should crop a number of words from the end of the message, keeping in mind that:

it may not crop away part of a word; the output message may not end with a space; the output message may not exceed the K-character limit; the output message should be as long as possible. This means that, in some cases, the algorithm may need to crop away the entire message, outputting an empty string

.

For example, given the text:

"Codility We test coders"

With K = 14 the algorithm should output:

"Codility We"

Note that:

the output "Codility We te" would be incorrect, because the original message is cropped through the middle of a word; the output "Codility We " would be incorrect, because it ends with a space; the output "Codility We test coders" would be incorrect, because it exceeds the K-character limit; the output "Codility" would be incorrect, because it is shorter than the correct output. Write a function

char * solution(char *message, int K);

which, given a message and an integer K, returns the message cropped to no more than K characters, as described above.

Examples:

1. Given message = "Codility We test coders" and K = 14, the function should return "Codility We".

2. Given message = "Why not" and K = 100, the function should return "Why not".

3. Given message = "The quick brown fox jumps over the lazy dog" and K = 39, the function should return "The quick brown fox jumps over the lazy".

4. Given message = "To crop or not to crop" and K = 21, the function should return "To crop or not to".

Assume that:

K is an integer within the range [1..500]; message is a non-empty string containing at most 500 English alphabet letters and spaces. There are no spaces at the beginning or at the end of message; also there can't be two or more consecutive spaces in message. In your solution, focus on correctness. The performance of your solution will not be the focus of the assessment.

CodePudding user response：

This code will pass all performance and correctness tests

char * (char *message, int K) {

    int N = strlen(message); // Length of message
    int last_index=0;
    // if length of message is less than Limit, just return the same message 
    if (N <= K){
      return message;
    }

    else{
    //find the space after last word without breaking the word
    for (int i = K; i > 0; i--){
        if(isspace(message[i])){
            last_index  = i;
            break;
        }
    }

    //trim the message by adding "end of string" to index we found in previous step
    message[last_index] = '\0';
   
    return message;
    }
}