hdu 3530 Subsequence (尺取+rmq)

 1#include <cstdio>
 2#include <cstring>
 3#include <iostream>
 4#include <algorithm>
 5#include <vector>
 6#include <queue>
 7#include <set>
 8#include <map>
 9#include <string>
10#include <cmath>
11#include <cstdlib>
12#include <ctime>
13#define fst first
14#define sec second
15#define lson l,m,rt<<1
16#define rson m+1,r,rt<<1|1
17#define ms(a,x) memset(a,x,sizeof(a))
18typedef long long LL;
19#define pi pair < int ,int >
20#define MP make_pair

 1using namespace std;
 2const double eps = 1E-8;
 3const int dx4[4]={1,0,0,-1};
 4const int dy4[4]={0,-1,1,0};
 5const int inf = 0x3f3f3f3f;
 6const int N=1E5+7;
 7int n;
 8int a[N];
 9int dp[N][20],dp2[N][20];
10int m,k;

1void rmq_init()
2{
3    for ( int i  = 1 ; i <= n ; i ++)
4	dp[i][0] = dp2[i][0] = a[i];

1    for ( int j = 1 ; (1<<j) <= n ; j++)
2	for ( int i = 1 ; i + (1<<j) -1 <= n ; i++)
3	{
4	    dp[i][j] = max(dp[i][j-1],dp[i+(1<<(j-1))][j-1]);
5	    dp2[i][j]=min(dp2[i][j-1],dp2[i+(1<<(j-1))][j-1]);
6	}
7}

1int rmq( int l,int r)
2{
3    int k = 0 ;
4    while (1<<(k+1)<=r-l+1) k++;
5    int mx = max(dp[l][k],dp[r-(1<<k)+1][k]);
6    int mn = min(dp2[l][k],dp2[r-(1<<k)+1][k]);

 1int ruler()
 2{
 3    int head = 1;
 4    int tail = 1;
 5    int res = -1 ;
 6    while (tail<=n)
 7    {
 8	int cur = rmq(head,tail);
 9	while (head<tail&&rmq(head,tail)>k) head++;
10	while (tail<n&&rmq(head,tail)<m) tail++;
11	//if (tail>n) break;
12	cur = rmq(head,tail);
13	if (cur>=m&&cur<=k)
14	{
15	    res = max(res,tail-head);
16	}
17//	cout<<"head:"<<head<<" tail:"<<tail<<" cur:"<<cur<<" res:"<<res<<endl;
18	tail++;

1    }
2    return res+1;
3}
4int main()
5{
6	#ifndef  ONLINE_JUDGE 
7	freopen("code/in.txt","r",stdin);
8  #endif

 1	while (scanf("%d %d %d",&n,&m,&k)!=EOF)
 2	{
 3	    ms(dp,0);
 4	    for ( int i = 1 ; i  <= n ; i++) scanf("%d",&a[i]);
 5	    if (m>k)
 6	    {
 7		puts("0");
 8		continue;
 9	    }
10	    rmq_init();
11	    printf("%d\n",ruler());
12	}

1  #ifndef ONLINE_JUDGE  
2  fclose(stdin);
3  #endif
4    return 0;
5}