UVa 514 Rails（stack）

又犯了输出错误，从现在起，以后没提交一道题之前，都必须要再审一遍输出

根据先进后出，可以推断，如果有一个这样的图形，r[i] > r[i-1] && r[i] < r[i-2] 那么就一定不符合

代码如下：

#include <cstdio>
#include <cstring>
using namespace std;

int n, rail[1010];

int main()
{
while ( scanf("%d", &n) != EOF && n ) {
while ( scanf("%d", &rail[0]), rail[0] ) {
bool is = true, now = true;
for ( int i = 1; i < n; ++i ) scanf("%d", &rail[i]);
for ( int i = 1; i < n; ++i )
if ( rail[i] < rail[i-1] ) now = 0;
else if ( now == 0 && ( rail[i] > rail[i-1] && rail[i] < rail[i-2] ) ) { is = false; break; }
else if ( now == 0 && ( rail[i] > rail[i-1] && rail[i] > rail[i-2] ) ) now = true;
if ( is ) printf("Yes\n");
else printf("No\n");
}
printf("\n");
}
}