68. Text Justification

解题思路

这是一个典型的分治算法，基本思路就是：扫描字符串数组，累加长度，当发现长度超过最大长度的时候，就把前面的几个字符串按规则组合，加入到List中。

public List<String> fullJustify(String[] words, int maxWidth) {        List<String> result = new ArrayList<>();        if(words==null||words.length==0)            return result;        if(maxWidth==0)        {            result.add("");            return result;        }        greedy(words,maxWidth,result);        return result;    }    public void greedy(String[] words,int maxWidth,List<String> result )    {        if(words==null||words.length==0)            return;        int sum = words[0].length();        int i;        for (i=1;i<words.length;i++)        {            sum += (words[i].length()+1);            if(sum>maxWidth)                break;        }        if(sum<=maxWidth)        {            String re = "";            if (words.length==1)            {                re += words[0];                for (int j=0;j<maxWidth-words[0].length();j++)                    re += " ";                result.add(re);                return;            }            int len = 0;            for (int j=0;j<words.length-1;j++)            {                len += (words[j].length()+1);                re += words[j];                re += " ";            }            re += words[words.length-1];            len += words[words.length-1].length();            for (int j =0;j<maxWidth-len;j++)                re += " ";            result.add(re);            return;        }        String[] s1 = Arrays.copyOfRange(words,0,i);        String[] s2 = Arrays.copyOfRange(words,i,words.length);        result.add(mergeString(s1,maxWidth));        greedy(s2,maxWidth,result);    }    public String mergeString(String[] words,int maxWidth)    {        String result = "";        int sum = 0;        for(int i=0;i<words.length;i++)            sum += words[i].length();        if (words.length==1)        {            result += words[0];            for (int i=0;i<maxWidth-words[0].length();i++)                result += " ";            return result;        }        int meanSpace = (maxWidth-sum)/(words.length-1);        int moreSpace = (maxWidth-sum)%(words.length-1);        for (int i=0;i<words.length-1;i++)        {            result += words[i];            for (int j=0;j<meanSpace;j++)                result += " ";            if(moreSpace>0)            {                result += " ";                moreSpace--;            }        }        result += words[words.length-1];        return  result;    }