Java for LeetCode 068 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 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.

解题思路：

直接按照约束条件老实实现即可，JAVA实现如下：

     static public List<String> fullJustify(String[] words, int maxWidth) {
        List<String> list=new ArrayList<String>();
        int start=0,end=-1,sum=0;
        for(int i=0;i<words.length;i++){
        	sum+=words[i].length();
        	if(sum>maxWidth){
        		i--;
        		start=end+1;
        		end=i;
        		sum=0;
        		list.add(oneString(words,start,end,maxWidth));
        		continue;
        	}
        	sum++;
        }
        if(sum>0)
        	list.add(oneString(words,end+1,words.length-1,maxWidth));
        return list;   
    }
    static public String oneString(String[] words,int start,int end,int maxWidth){
    	StringBuilder sb=new StringBuilder();
    	if(start==end)
    		sb.append(words[start]);
    	else if(end==words.length-1){
    		for(int i=start;i<=end-1;i++)
    			sb.append(words[i]+" ");
    		sb.append(words[end]);
    	}
    	else{
    	    int spaceSum=maxWidth;
    	    for(int i=start;i<=end;i++)
    		    spaceSum-=words[i].length();
    		int extra=spaceSum-(spaceSum/(end-start))*(end-start);
    		for(int i=start;i<=end;i++){
    			sb.append(words[i]);
    			for(int j=0;j<spaceSum/(end-start)&&i!=end;j++)
    				sb.append(" ");
    			if(extra-->0)
    				sb.append(" ");
    		}
    	}
    	while(sb.length()<maxWidth)
    		sb.append(" ");
    	return sb.toString();
    }