bzoj1088

辣鸡题。。

省选考模拟 简直良心。。

#include <cstdio>
int n,a[10010],b[10010];

int read_int () {
	char c = getchar();
	int re = 0;
	for(;c > '9' || c < '0';c = getchar());
	for(;c >= '0' && c <= '9';c = getchar())
		re = re * 10 + c - '0';
	return re;
}

int hehe () {
	for(int i = 2;i <= n;++i) {
		if(b[i - 1] < 0)
			return 0;
		if(b[i - 1] == 1) {
			--b[i - 1];
			--b[i];
			--b[i + 1];
		}
	}
	if(b[n] != 0)
		return 0;
	return 1;
}

int main () {
	n = read_int();
	for(int i = 1;i <= n;++i)
		b[i] = a[i] = read_int();
	--b[1];--b[2];
	int t = hehe();
	for(int i = 1;i <= n;++i)
		b[i] = a[i];
	t += hehe();
	printf("%d\n",t);
}