记录编号	22175	评测结果	AAAWWWWWWA
题目名称	拯救	最终得分	40
用户昵称	wangwangdog	是否通过	未通过
代码语言	C++	运行时间	0.005 s
提交时间	2010-11-17 15:39:00	内存使用	0.28 MiB

#include<stdio.h>
long long i,n,a[1001],da[1001],db[1001],dc[1001];
char cc;
int main()
{
	FILE *fin,*fout;
	fin=fopen("savey.in","rb");
	fout=fopen("savey.out","wb");
	fscanf(fin,"%lld\n",&n);
	for(i=1;i<=n;i++)
	{
		fscanf(fin,"%lld",&a[i]);
	}
	if(n==1)
	{
		if(a[1]==0)fprintf(fout,"0");
		if(a[1]==1)fprintf(fout,"1");
	}
	if(n==2)
	{
		if(a[1]==1&&a[2]==1)fprintf(fout,"2");
		if(a[1]==1&&a[2]==0)fprintf(fout,"1");
		if(a[1]==0&&a[2]==1)fprintf(fout,"3");
		if(a[1]==0&&a[2]==0)fprintf(fout,"0");
	}
	if(n!=1&&n!=2)
	{
		da[1]=a[1];
		if(a[1]==1)db[1]=0;
		else db[1]=1;
		dc[1]=1;
		for(i=2;i<=n;i++)
		{
			if(a[i]==0)
			{
				da[i]=da[i-1];
				db[i]=db[i-1]+1+dc[i-1];
				dc[i]=dc[i-1]+1+dc[i-1];
					
			}
			if(a[i]==1)
			{
				db[i]=da[i-1]; 
				da[i]=db[i-1]+1+dc[i-1];
				dc[i]=dc[i-1]+dc[i-1]+1;
					
			}
		}
		fprintf(fout,"%lld",da[n]);
	}
	fclose(fin);
	fclose(fout);
	return 0;
}