屏幕上能输出句子几遍

Given a rows x cols screen and a sentence represented by a list of 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 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.

int wordsTyping(vector<string>& sentence, int rows, int cols) {
    // 把word+" "+word+" "+...无限扩展
    string s;
    for (auto &word : sentence)
        s += word + " ";
    int len = s.size();
    
    int cnt = 0; // 总共输入了多少字符
    for (int i = 0; i < rows; i++) {
        cnt += cols; // 尝试键入一满行
        while (cnt > 0 && s[cnt % len] != ' ') // 若对着单词中间则回退
            cnt--;
        cnt++;   // 跳过空格
    }
    return cnt / len;
}