🌕 68. 文本左右对齐

难度: 🌕

问题描述

---

解法

class Solution {
    public List<String> fullJustify(String[] words, int maxWidth) {
        // 思路：
        // 依次放入每行的单词，单词间至少一个空格隔开
        int len = words.length;
        List<String> res = new ArrayList<>();
        List<String> list = new ArrayList<>();
        int preWord = 0; // 仅单词长度
        int preLen = 0; // 单词 + 空格长度
        int i = 0;
        while(i < len) {
            String cur = words[i];
            if(preLen + cur.length() <= maxWidth) {
                list.add(cur);
                preWord += cur.length();
                preLen += cur.length() + 1;
            } else {
                // print(list);
                // System.out.println(preWord);
                res.add(getStr(list, maxWidth, preWord));
                list = new ArrayList<>();
                list.add(cur);
                preWord = cur.length();
                preLen = cur.length() + 1;
            }
            i ++;
        }
        res.add(getLeft(list, maxWidth));
        return res;
    }

    private void print(List<String> list) {
        System.out.println();
        for(String str: list) {
            System.out.print(str + "  ");
        }
    }

    private String getLeft(List<String> list, int maxWidth) {
        StringBuilder sb = new StringBuilder();
        int len = list.size();
        for(int i = 0; i < len - 1; i ++) {
            sb.append(list.get(i)).append(' ');
        }
        sb.append(list.get(len - 1));
        int left = maxWidth - sb.length();
        sb.append(getSpace(left));
        return sb.toString();
    }

    private String getStr(List<String> list, int maxWidth, int preWord) {
        StringBuilder sb = new StringBuilder();
        int len = list.size();
        int space = maxWidth - preWord; // 总空格数
        if(len == 1) {
            sb.append(list.get(0));
            sb.append(getSpace(space));
            return sb.toString();
        }
        
        int avg = space / (len - 1); // 每个单词分配的空格数
        int left = space % (len - 1); // 左侧有 left 个空格数要多一个
        sb.append(list.get(0));
        for(int i = 0; i < left; i ++) {
            sb.append(getSpace(avg + 1));
            sb.append(list.get(i + 1));
        }
        for(int i = left; i < len - 1; i ++) {
            sb.append(getSpace(avg));
            sb.append(list.get(i + 1));
        }
        // sb.append(list.get(len - 1));
        return sb.toString();
    }

    private String getSpace(int n) {
        StringBuilder sb = new StringBuilder();
        for(int i = 0; i < n; i ++) {
            sb.append(' ');
        }
        return sb.toString();
    }
}

---

输出