[LeetCode] 117: Text Justification

[Problem]

Given an array of words and a length L, format the text such that each line has exactly L characters and is fully (left and right) justified.

You should pack your words in a greedy approach; that is, pack as many words as you can in each line. Pad extra spaces ' ' when necessary so that each line has exactly L characters.

Extra spaces between words should be distributed as evenly as possible. If the number of spaces on a line do not divide evenly between words, the empty slots on the left will be assigned more spaces than the slots on the right.

For the last line of text, it should be left justified and no extra space is inserted between words.

For example,
words: ["This", "is", "an", "example", "of", "text", "justification."]
L: 16.

Return the formatted lines as:

[
   "This    is    an",
   "example  of text",
   "justification.  "
]

Note: Each word is guaranteed not to exceed L in length.

Corner Cases:

• A line other than the last line might contain only one word. What should you do in this case?
  In this case, that line should be left-justified.

[Solution]

class Solution {
public:
	// generate result for a line
	string generateResult(vector<string> line, int L){
		// only one word
		if(line.size() == 1){
			return line[0] + string(L - line[0].size(), ' ');
		}

		// get the total length of the words
		int total = 0;
		for(int i = 0; i < line.size(); ++i)total += line[i].size();

		// get the blank mode
		int blanks = (L-total) / (line.size()-1);
		int remains = (L-total) % (line.size()-1);

		// generate result
		string res;
		for(int i = 0; i < line.size(); ++i){
			if(i == 0){
				res += line[i];
			}
			else{
				if(i <= remains){
					res += string(blanks + 1, ' ');
				}
				else{
					res += string(blanks, ' ');
				}
				res += line[i];
			}
		}
		return res;
	}
	// full justify
	vector<string> fullJustify(vector<string> &words, int L) {
		// Note: The Solution object is instantiated only once and is reused by each test case.
		
		// result
		vector<string> res;

		// get the max length of words
		int len = 0;
		for(int i = 0; i < words.size(); ++i){
			len = len > words[i].size() ? len : words[i].size();
		}
		if(L < len)return res;

		// justify
		len = 0;
		vector<string> line;
		for(int i = 0; i < words.size(); ++i){
			// add a blank
			if(len != 0){
				len++;
			}
			len += words[i].size();

			// full, trace back
			if(len > L){
				// add result
				res.push_back(generateResult(line, L));

				// update
				line.clear();
				line.push_back(words[i]);
				len = words[i].size();
			}
			else{
				line.push_back(words[i]);

				// add result
				if(len == L){
					res.push_back(generateResult(line, L));

					// update
					line.clear();
					len = 0;
				}
			}
		}
		if(line.size() > 0){
			len = 0;
			string tmp = "";
			for(int i = 0; i < line.size(); ++i){
				if(len != 0){
					tmp += " ";
					len++;
				}
				tmp += line[i];
				len += line[i].size();
			}
			tmp += string(L-len, ' ');
			res.push_back(tmp);
		}
		return res;
	}
};

说明：版权所有，转载请注明出处。 Coder007的博客