Leetcode 418. Sentence Screen Fitting

Given a rows x cols screen and a sentence represented by a list of non-empty words, find how many times the given sentence can be fitted on the screen.

Note:

1. A word cannot be split into two lines.
2. The order of words in the sentence must remain unchanged.
3. Two consecutive words in a line must be separated by a single space.
4. Total words in the sentence won't exceed 100.
5. Length of each word is greater than 0 and won't exceed 10.
6. 1 ≤ rows, cols ≤ 20,000.

Example 1:

Input:
rows = 2, cols = 8, sentence = ["hello", "world"]

Output: 
1

Explanation:
hello---
world---

The character '-' signifies an empty space on the screen.

Example 2:

Input:
rows = 3, cols = 6, sentence = ["a", "bcd", "e"]

Output: 
2

Explanation:
a-bcd- 
e-a---
bcd-e-

The character '-' signifies an empty space on the screen.

Example 3:

Input:
rows = 4, cols = 5, sentence = ["I", "had", "apple", "pie"]

Output: 
1

Explanation:
I-had
apple
pie-I
had--

The character '-' signifies an empty space on the screen.

Code (Java):

class Solution {
    public int wordsTyping(String[] sentence, int rows, int cols) {
        String str = "";
        
        for (String word : sentence) {
            str += word + " ";
        }
        
        int len = str.length();
        
        int start = 0;
        for (int i = 0; i < rows; i++) {
            start += cols;
            
            if (str.charAt(start % len) == ' ') {
                start++;
                continue;
            }
            
            while ((start % len - 1 >= 0) && str.charAt(start % len - 1) != ' ') {
                start--;
            }
        }
        
        return start / len;
    }
}