UVA848 Fmt文本处理

Posted 2021-09-01 海岛Blog

The unix fmt program reads lines of text, combining and breaking lines so as to create an output file with lines as close to without exceeding 72 characters long as possible. The rules for combining and breaking lines are as follows.
• A new line may be started anywhere there is a space in the input. If a new line is started, there will be no trailing blanks at the end of the previous line or at the beginning of the new line.
• A line break in the input may be eliminated in the output, provided it is not followed by a space or another line break. If a line break is eliminated, it is replaced by a space.
• Spaces never appear at the end of a line.
• If a sequence of characters longer than 72 characters appears without a space or line break, it appears by itself on a line.
Sample Input

   Unix fmt
   
The unix fmt program reads lines of text, combining
and breaking lines so as to create an
output file with lines as close to without exceeding
72 characters long as possible. The rules for combining and breaking
lines are as follows.

   1. A new line may be started anywhere there is a space in the input.
If a new line is started, there will be no trailing blanks at the
end of the previous line or at the beginning of the new line.

   2. A line break in the input may be eliminated in the output, provided
it is not followed by a space or another line break. If a line
break is eliminated, it is replaced by a space.

Sample Output

Unix fmt

The unix fmt program reads lines of text, combining and breaking lines
so as to create an output file with lines as close to without exceeding
72 characters long as possible. The rules for combining and breaking
lines are as follows.

   1. A new line may be started anywhere there is a space in the
input. If a new line is started, there will be no trailing blanks at
the end of the previous line or at the beginning of the new line.

   2. A line break in the input may be eliminated in the output,
provided it is not followed by a space or another line break. If a
line break is eliminated, it is replaced by a space.

问题链接：UVA848 Fmt
问题简述：（略）
问题分析：文本处理问题，不解释。
程序说明：（略）
参考链接：（略）
题记：（略）

AC的C++语言程序如下：

/* UVA848 Fmt */

#include <bits/stdc++.h>

using namespace std;

void output(string & s)
{
    while (s.size() > 0 && s.back() == ' ')
        s.pop_back();
    puts(s.c_str());
}

int main()
{
    string line, last;
    while (getline(cin, line)) {
        if (line.empty()) {
            if (!last.empty()) output(last);
            output(line);
            last = line;
        } else {
            if (line[0] == ' ') {
                if (!last.empty()) output(last);
                last.clear();
            } else if (!last.empty())
                line = ' ' + line;
            for (int i = 0; i < (int)line.size(); i++) {
                if (line[i] == ' ') last += ' ';
                else {
                    int j = i;
                    while (j < (int)line.size() && line[j] != ' ') j++;
                    if (last.size() + j - i > 72) {
                        if (!last.empty()) {
                            output(last);
                            last.clear();
                        }
                    }
                    last += line.substr(i, j - i);
                    i = j - 1;
                }
            }
        }
    }
    if (!last.empty()) output(last);

    return 0;
}