123.c

平时acm训练时ac的源代码

/*
123. The sum 
Accepted 98 ms 114 kb 
*/

#include <stdio.h>

int main()
{
	int K, i;
	long S=0, arr[41];
	arr[0] = 1;
	arr[1] = 1;
	scanf("%d", &K);
	for (i=2; i<K; i++)
	{
		arr[i] = arr[i-1]+arr[i-2];
	}
	for (i=0; i<K; i++)
	{
		S += arr[i];
	}
	printf("%ld", S);
}