文本左右对齐

学习

一、题目

这个问题是一个典型的文本排版问题。

二、解题思路

• 初始化：创建一个结果列表result来存储每一行的文本，以及一个临时列表current_line来存储当前正在构建的行的单词。

• 贪心算法填充：遍历words数组，使用贪心算法尽可能多地将单词放入current_line，直到无法再添加更多单词而不超出maxWidth。

• 分配空格：当current_line中的单词不能再添加更多单词时，计算需要添加的空格数以使该行的总长度达到maxWidth。如果单词间的空格不能均匀分配，则左侧多于右侧。

• 构建行：根据计算出的空格数，构建当前行的文本，并添加到result中。

• 最后一行特殊处理：对于最后一行，如果是左对齐，且单词之间不插入额外的空格。

• 返回结果：完成所有行的构建后，返回result列表。

python代码

def fullJustify(words, maxWidth):
    result = []
    i = 0
    while i < len(words):
        count = 0  # 记录当前行单词的数量
        width = 0  # 当前行的总宽度
        for j in range(i, len(words)):
            if width + len(words[j]) + count <= maxWidth:
                count += 1
                width += len(words[j])
            else:
                break

        line = []
        if count == 1 or i + count == len(words):  # 如果只有1个单词或最后一行
            line = ' '.join(words[i:i + count])
        else:  # 多于1个单词且不是最后一行
            spaces = maxWidth - width
            spaceBetween = spaces // (count - 1)  # 每个单词间空格数
            extraSpaces = spaces % (count - 1)  # 多出的空格数
            for j in range(count):
                line.append(words[i + j])
                if j < count - 1:
                    line.extend([' '] * (spaceBetween + (1 if extraSpaces > 0 else 0)))
                    if extraSpaces > 0:
                        extraSpaces -= 1

        result.append(''.join(line))
        i += count  # 移动到下一行的开始

    return result

# 示例用法
if __name__ == "__main__":
    words1 = ["This", "is", "an", "example", "of", "text", "justification."]
    maxWidth1 = 16
    for line in fullJustify(words1, maxWidth1):
        print(line)

    words2 = ["What", "must", "be", "acknowledgment", "shall", "be"]
    maxWidth2 = 16
    for line in fullJustify(words2, maxWidth2):
        print(line)

    words3 = ["Science", "is", "what", "we", "understand", "well", "enough", "to", "explain", "to", "a", "computer", ".", "Art", "is", "everything", "else", "we", "do"]
    maxWidth3 = 20
    for line in fullJustify(words3, maxWidth3):
        print(line)


# 示例用法
words1 = ["This", "is", "an", "example", "of", "text", "justification."]
maxWidth1 = 16
print("\n".join(fullJustify(words1, maxWidth1)))

words2 = ["What", "must", "be", "acknowledgment", "shall", "be"]
maxWidth2 = 16
print("\n".join(fullJustify(words2, maxWidth2)))

words3 = ["Science", "is", "what", "we", "understand", "well", "enough", "to", "explain", "to", "a", "computer.", "Art", "is", "everything", "else", "we", "do"]
maxWidth3 = 20
print("\n".join(fullJustify(words3, maxWidth3)))