对拍 & 随机数生成

用 Windows 批处理对拍：

1. 新建一个批处理（.bat），代码如下：

:loop
@echo off
data_creator.exe
force_solution.exe
correct_solution.exe
@echo on
fc force_solution.out correct_solution.out
if not errorlevel 1 goto loop
pause

2. 创建一个数据生成程序，一个暴力程序，一个正解。

3. 循环运行这个批处理，对照 correct_solution 和 force_solution 的答案是否相同。

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随机数生成器 Example（Data_Creator.cpp）

The function random(a, b) creates integers in the range [a, b]. The function randll(a, b) creates Int64 integers in the range [a, b].

Sentence srand(time(0)); is needed.

/* Data Creator
 * Au: GG
 */
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <ctime>
#include <iostream>
#include <algorithm>
using namespace std;

// Create a random in range [a, b].
// It can only create integers.
int random(int a, int b) {
    if (rand() % 2)
        return (rand() * 32768 + rand()) % (b - a + 1) + a;
    else return (rand() * 32768 - rand()) % (b - a + 1) + a;
}

// Create a random in range [a, b]
// Supports Int64 numbers.
long long randll(long long a, long long b) {
    if (rand() % 2)
        return ((long long)random(0, 2147483647) * 2147483648ll + random(0, 2147483647)) % (b - a + 1) + a;
    else return ((long long)random(0, 2147483647) * 2147483648ll - random(0, 2147483647)) % (b - a + 1) + a;
}

int n1, n2, a1, b1, a2, b2;

int main() {
    freopen("data.out", "w", stdout); // write to file
    srand(time(0)); // create a random seed

    scanf("%d%d%d", &n1, &a1, &b1);
    scanf("%d%d%d", &n2, &a2, &b2);
    for (int i = 1; i <= n1; i++)
        printf("%d
", random(a1, b1));
    for (int i = 1; i <= n2; i++)
        printf("%lld
", randll(a2, b2));

    return 0;
}

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srand(time(NULL)) 也是可行的，但不 secure。参见 https://stackoverflow.com/questions/26206780/is-srandtimenull-bad。

另外一种对拍方法：“管道”，即命令行参数。参见 http://blog.csdn.net/wlx65003/article/details/51149196。