pku2769.cpp

这是ACM 方面的资料 是PKU的 北京大学的出来的

#include <stdio.h>
#include <memory.h>
#define maxn 1000000

int N;
int a[300];
int stack[300];
int top;
char v[maxn];
char c[maxn];

int abs(int x){return x > 0 ? x : -x;}

int check(int x)
{
	int i, tmp;
	while (top > 0)
		v[stack[--top]] = 0;
	for (i = 0; i < N; i++)
	{
		tmp = a[i] % x;
		if (v[tmp])
			return 0;
		v[tmp] = 1;
		stack[top++] = tmp;
	}
	return 1;
}

void Solve()
{
	int i, j;
	int p;
	for (i = 0; i < N; i++)
		scanf("%d", a + i);
	memset(c, 0, sizeof(c));
	memset(v, 0, sizeof(v));
	for (i = 0; i < N; i++)
		for (j = i + 1; j < N; j++)
			c[abs(a[i] - a[j])] = 1;
	top = 0;
	p = N;
	while (1)
	{
		if (!c[p])
			if (check(p))
			{
				printf("%d\n", p);
				return;
			}
		p++;
	}
}

int main()
{
	int T;
	scanf("%d", &T);
	while (T-- && EOF != scanf("%d", &N) && N)
		Solve();
	return 0;
}