BZOJ 1113 海报 单调栈

 1 #include<bits/stdc++.h>
 2 #define IOS ios::sync_with_stdio(false);//不可再使用scanf printf
 3 #define Max(a, b) ((a) > (b) ? (a) : (b))//禁用于函数，会超时
 4 #define Min(a, b) ((a) < (b) ? (a) : (b))
 5 #define Mem(a) memset(a, 0, sizeof(a))
 6 #define Dis(x, y, x1, y1) ((x - x1) * (x - x1) + (y - y1) * (y - y1))
 7 #define MID(l, r) ((l) + ((r) - (l)) / 2)
 8 #define lson ((o)<<1)
 9 #define rson ((o)<<1|1)
10 #define Accepted 0
11 #pragma comment(linker, "/STACK:102400000,102400000")//栈外挂
12 using namespace std;
13 inline int read()
14 {
15     int x=0,f=1;char ch=getchar();
16     while (ch<‘0‘||ch>‘9‘){if (ch==‘-‘) f=-1;ch=getchar();}
17     while (ch>=‘0‘&&ch<=‘9‘){x=x*10+ch-‘0‘;ch=getchar();}
18     return x*f;
19 }
20 typedef long long ll;
21 const int maxn = 1000000 + 10;
22 const int MOD = 1000000007;//const引用更快，宏定义也更快
23 const int INF = 1e9 + 7;
24 const double eps = 1e-6;
25 
26 stack<int>q;
27 int main()
28 {
29     int n, ans = 0, x, y;
30     scanf("%d", &n);
31     for(int i = 1; i <= n; i++)
32     {
33         scanf("%d%d", &x, &y);
34         while(!q.empty() && q.top() > y)
35         {
36             q.pop();
37             ans++;
38         }
39         if(!q.empty() && q.top() == y)continue;
40         q.push(y);
41     }
42     ans += q.size();
43     printf("%d\n", ans);
44     return Accepted;
45 }