造数据

随机字符串

import random, string
random_str = ''.join(random.choice(string.ascii_lowercase) for _ in range(800000))
print(random_str, file= open("5.in", "w"))

string库/usr/lib/python3.8/string.py

"""
whitespace -- a string containing all ASCII whitespace
ascii_lowercase -- a string containing all ASCII lowercase letters
ascii_uppercase -- a string containing all ASCII uppercase letters
ascii_letters -- a string containing all ASCII letters
digits -- a string containing all ASCII decimal digits
hexdigits -- a string containing all ASCII hexadecimal digits
octdigits -- a string containing all ASCII octal digits
punctuation -- a string containing all ASCII punctuation characters
printable -- a string containing all ASCII characters considered printable
"""

whitespace = ' \t\n\r\v\f'
ascii_lowercase = 'abcdefghijklmnopqrstuvwxyz'
ascii_uppercase = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
ascii_letters = ascii_lowercase + ascii_uppercase
digits = '0123456789'
hexdigits = digits + 'abcdef' + 'ABCDEF'
octdigits = '01234567'
punctuation = r"""!"#$%&'()*+,-./:;<=>?@[\]^_`{|}~"""
printable = digits + ascii_letters + punctuation + whitespace

测试时间 重新导向控制台

#include <stdio.h>
#include <string.h>
#include <time.h>
#define N 1000005
char s[N], t[N];
int main() {
    freopen("5.in", "r", stdin);
    freopen("5.out", "w", stdout);
    time_t begin_t = clock();
    while (~scanf("%s", s)) {
        int n = strlen(s), cnt = 0, j = 0;
        for (int i = 0; i < n; ++i)
            if (s[i] == 'x') ++cnt;
            else t[j++] = s[i];
        for (int i = 0; i < cnt; ++i) t[j++] = 'x';
        t[j] = 0;
        puts(t);
    }
    freopen("CON", "w", stdout);
    time_t finish_t = clock();
    printf("it cost %lf s\n", (double)(finish_t - begin_t) / CLOCKS_PER_SEC);
    return 0;
}

需要注意，这里其实没有真正关闭，只是再次重定向，回到控制台。

在windows/DOS，读文件后用freopen("CON", "r", stdin)，写文件后 freopen("CON","w", stdout)。

在linux中，控制台设备是 /dev/console：freopen("/dev/console", "r", stdin)。