题目描述

题目：文本左右对齐

给定一个字符串（代表一行文本）和一个整数maxWidth（表示每行允许的最大字符数，包括空格），要求将该字符串按照以下规则重新排列，使其左右对齐，并返回处理后的多行字符串数组。

• 字符串中的单词由空格分隔。
• 超出maxWidth的单词需要被移到新的一行。
• 每行末尾的空格数应该尽可能均匀分布（如果可能），但左对齐是首要条件。
• 如果一行的单词数量只有一个或者没有足够的空格均匀分布，则该行单词左对齐，并在右侧填充空格以达到maxWidth。

示例

输入:

str = "The quick brown fox jumps over the lazy dog"
maxWidth = 16

输出:

["The  quick brown",
 "fox  jumps  over",
 "the   lazy dog"]

PHP 代码示例

function fullJustify($words, $maxWidth) {
    $result = [];
    $line = [];
    $lineLength = 0;

    foreach ($words as $word) {
        $wordLength = strlen($word) + 1; // 加1是因为单词间的空格
        if ($lineLength + $wordLength > $maxWidth) {
            $result[] = justifyLine($line, $maxWidth, count($line) > 1);
            $line = [$word];
            $lineLength = strlen($word);
        } else {
            $line[] = $word;
            $lineLength += $wordLength;
        }
    }

    // 处理最后一行
    if (!empty($line)) {
        $spaces = $maxWidth - $lineLength;
        $n = count($line) - 1;
        $result[] = implode(str_repeat(' ', ceil($spaces / $n)), array_slice($line, 0, -1)) . ' ' . end($line);
        for ($i = 0; $i < $maxWidth - strlen(end($result)); $i++) {
            end($result) .= ' ';
        }
    }

    return $result;
}

function justifyLine($line, $maxWidth, $fullJustify) {
    $n = count($line) - 1;
    $lineStr = implode(' ', $line);
    $spaces = $maxWidth - strlen($lineStr);

    if ($fullJustify && $n > 0) {
        $extraSpaces = $spaces % $n;
        $avgSpaces = intdiv($spaces, $n);
        $justifiedLine = '';
        for ($i = 0; $i < $n; $i++) {
            $justifiedLine .= $line[$i] . str_repeat(' ', $avgSpaces + ($i < $extraSpaces ? 1 : 0)) . ' ';
        }
        $justifiedLine .= $line[$n];
    } else {
        $justifiedLine = $lineStr . str_repeat(' ', $spaces);
    }

    return rtrim($justifiedLine);
}

// 示例用法
$words = explode(' ', "The quick brown fox jumps over the lazy dog");
$maxWidth = 16;
$result = fullJustify($words, $maxWidth);
print_r($result);

Python 代码示例

def fullJustify(words, maxWidth):
    result = []
    line = []
    line_length = 0

    for word in words:
        word_length = len(word) + 1  # 加1考虑空格
        if line_length + word_length > maxWidth:
            result.append(justify_line(line, maxWidth, len(line) > 1))
            line = [word]
            line_length = len(word)
        else:
            line.append(word)
            line_length += word_length

    # 处理最后一行
    if line:
        spaces = maxWidth - line_length + len(line) - 1
        result.append(' '.join(line) + ' ' * spaces)
        result[-1] = result[-1].rstrip()

    return result

def justify_line(line, maxWidth, full_justify):
    n = len(line) - 1
    line_str = ' '.join(line)
    spaces = maxWidth - len(line_str)

    if full_justify and n > 0:
        extra_spaces = spaces % n
        avg_spaces = spaces // n
        justified_line = ''
        for i in range(n):
            justified_line += line[i] + ' ' * (avg_spaces + (1 if i < extra_spaces else 0))
        justified_line += line[-1]
    else:
        justified_line = line_str + ' ' * spaces

    return justified_line.rstrip()

# 示例用法
words = "The quick brown fox jumps over the lazy dog".split()
maxWidth = 16
result = fullJustify(words, maxWidth)
print(result)

JavaScript 代码示例

function fullJustify(words, maxWidth) {
    const result = [];
    let line = [];
    let lineLength = 0;

    for (let word of words) {
        const wordLength = word.length + 1; // 加1考虑空格
        if (lineLength + wordLength > maxWidth) {
            result.push(justifyLine(line, maxWidth, line.length > 1));
            line = [word];
            lineLength = word.length;
        } else {
            line.push(word);
            lineLength += wordLength;
        }
    }

    // 处理最后一行
    if (line.length) {
        const spaces = maxWidth - (line.reduce((sum, word) => sum + word.length, 0) - line.length + 1);
        result.push(line.join(' ') + ' '.repeat(spaces).slice(0, spaces));
    }

    return result;
}

function justifyLine(line, maxWidth, fullJustify) {
    const n = line.length - 1;
    const lineStr = line.join(' ');
    let spaces = maxWidth - lineStr.length;

    if (fullJustify && n > 0) {
        const extraSpaces = spaces % n;
        const avgSpaces = Math.floor(spaces / n);
        let justifiedLine = '';
        for (let i = 0; i < n; i++) {
            justifiedLine += line[i] + ' '.repeat(avgSpaces + (i < extraSpaces ? 1 : 0)) + ' ';
        }
        justifiedLine += line[n];
    } else {
        justifiedLine = lineStr + ' '.repeat(spaces);
    }

    return justifiedLine.trim();
}

// 示例用法
const words = "The quick brown fox jumps over the lazy dog".split(' ');
const maxWidth = 16;
const result = fullJustify(words, maxWidth);
console.log(result);

以上代码均实现了文本左右对齐的功能，并处理了各种边界情况。