题目:
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:
- A word cannot be split into two lines.
- The order of words in the sentence must remain unchanged.
- Two consecutive words in a line must be separated by a single space.
- Total words in the sentence won't exceed 100.
- Length of each word is greater than 0 and won't exceed 10.
- 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.
思路:
在网上看到一个巧妙的方法:把所有的字符串都加起来,然后每次看如果位移一整行的距离是否正好落在这个字符串的空格位置,如果不是的话就退后,直到遇到一个空格。
代码:
class Solution {
public:
int wordsTyping(vector<string>& sentence, int rows, int cols) {
string str;
for(auto val: sentence) {
str += val + " ";
}
int len = str.size(), start = 0;
for(int i = 0; i < rows; i++) {
start += cols;
if(str[start % len] == ' ') {
++start;
continue;
}
while(start > 0 && str[(start - 1) % len] != ' ') {
--start;
}
}
return start / len;
}
};