bzoj 1113 [Poi2008]海报PLA 单调栈

[Poi2008]海报PLA

Time Limit: 10 Sec Memory Limit: 162 MB
Submit: 1304 Solved: 896
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Description

N个矩形,排成一排. 现在希望用尽量少的矩形海报Cover住它们.

Input

第一行给出数字N,代表有N个矩形.N在[1,250000] 下面N行,每行给出矩形的长与宽.其值在[1,1000000000]2 1/2 Postering

Output

最少数量的海报数.

Sample Input

5
1 2
1 3
2 2
2 5
1 4

Sample Output

HINT

直接单调栈吧，怎么搞都行

 1 #include<iostream>
 2 #include<cstdio>
 3 #include<cmath>
 4 #include<algorithm>
 5 #include<cstring>
 6 #define F(i,j,n) for(int i=j;i<=n;i++)
 7 #define D(i,j,n) for(int i=j;i>=n;i--)
 8 #define LL long long
 9 #define MAXN 250005
10 using namespace std;
11 int ans,n,x,y,s[MAXN],t=0;
12 int main()
13 {
14     scanf("%d",&n);
15     ans=n;
16     scanf("%d%d",&x,&y);
17     s[++t]=y;
18     F(i,2,n)
19     {
20         scanf("%d%d",&x,&y);
21         while (t>0&&s[t]>y) t--;
22         if (s[t]==y) ans--;
23         s[++t]=y;
24     }
25     printf("%d
",ans);
26 }