[LeetCode] Text Justification

Text Justification

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 exactlyL 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.

click to show corner cases.

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.

解题思路：

题意为将句子的词按两端对齐。

题目本身不难，就是分情况讨论即可。

class Solution {
public:
    vector<string> fullJustify(vector<string>& words, int maxWidth) {
        vector<string> result;
        
        int len = words.size();
        int i = 0;
        while(i < len){
            int lineLen = words[i].length();
            int j = i + 1;
            while(j<len && lineLen + 1 + words[j].length() <= maxWidth){
                lineLen = lineLen + 1 + words[j].length();
                j++;
            }
            
            string line = words[i];
            
            if(j == len){   //表示为最后一行
                for(int m = i + 1; m<j; m++){
                    line = line + " " + words[m];
                }
                while(line.length() < maxWidth){
                    line = line + " ";
                }
            }else{          //表示中间行
                int leftSpace = maxWidth - lineLen; //中间还需要插入的空格数
                int spaceNumber = j - i - 1;        //词数减一，表示中间的空白数
                if(spaceNumber == 0){              //只有一个词
                    while(line.length() < maxWidth){
                        line = line + " ";
                    }
                }else{
                    int addedSpaceNum = leftSpace / spaceNumber;
                    int extra = leftSpace % spaceNumber;
                    for(int m = i + 1; m < j; m++){
                        line = line + " ";
                        for(int n = 0; n<addedSpaceNum; n++){
                            line = line + " ";
                        }
                        if(extra>0){
                            line = line + " ";
                            extra--;
                        }
                        line = line + words[m];
                    }
                }
            }
            result.push_back(line);
            i = j;
        }
        
        return result;
    }
};