1951800_ac_30ms_132k.c

北大大牛代码 1240道题的原代码 超级权威

# include <stdio.h>
# include <stdlib.h>

int cmp(const void *a, const void *b)
{
	return *(__int64 *)a - *(__int64 *)b;
}

int main()
{
	__int64 i, n;
	__int64 data[10001];
	__int64 sum, total, tmp;

	scanf("%I64d",&n);
	sum = total = tmp = 0;
	for(i = 0; i < n; i++)
	{
		scanf("%I64d",&data[i]);
		sum += data[i];
	}
	qsort(data,n,sizeof(data[0]),cmp);
	for(i = 0; i < n; i++)
	{
		tmp += data[i];
		total += sum-tmp-(n-i-1)*data[i]+i*data[i]-(tmp-data[i]);
	}
	printf("%I64d\n",total);
	return 1;
}