hdu 3530 Subsequence (尺取+rmq)

  1/* ***********************************************
  2Author :111qqz
  3Created Time :2016年05月19日 星期四 16时52分03秒
  4File Name :code/hdu/3530.cpp
  5************************************************ */
  6
  7#include <cstdio>
  8#include <cstring>
  9#include <iostream>
 10#include <algorithm>
 11#include <vector>
 12#include <queue>
 13#include <set>
 14#include <map>
 15#include <string>
 16#include <cmath>
 17#include <cstdlib>
 18#include <ctime>
 19#define fst first
 20#define sec second
 21#define lson l,m,rt<<1
 22#define rson m+1,r,rt<<1|1
 23#define ms(a,x) memset(a,x,sizeof(a))
 24typedef long long LL;
 25#define pi pair < int ,int >
 26#define MP make_pair
 27
 28using namespace std;
 29const double eps = 1E-8;
 30const int dx4[4]={1,0,0,-1};
 31const int dy4[4]={0,-1,1,0};
 32const int inf = 0x3f3f3f3f;
 33const int N=1E5+7;
 34int n;
 35int a[N];
 36int dp[N][20],dp2[N][20];
 37int m,k;
 38
 39void rmq_init()
 40{
 41    for ( int i  = 1 ; i <= n ; i ++)
 42	dp[i][0] = dp2[i][0] = a[i];
 43
 44    for ( int j = 1 ; (1<<j) <= n ; j++)
 45	for ( int i = 1 ; i + (1<<j) -1 <= n ; i++)
 46	{
 47	    dp[i][j] = max(dp[i][j-1],dp[i+(1<<(j-1))][j-1]);
 48	    dp2[i][j]=min(dp2[i][j-1],dp2[i+(1<<(j-1))][j-1]);
 49	}
 50}
 51
 52int rmq( int l,int r)
 53{
 54    int k = 0 ;
 55    while (1<<(k+1)<=r-l+1) k++;
 56    int mx = max(dp[l][k],dp[r-(1<<k)+1][k]);
 57    int mn = min(dp2[l][k],dp2[r-(1<<k)+1][k]);
 58
 59    return mx-mn;
 60}
 61
 62int ruler()
 63{
 64    int head = 1;
 65    int tail = 1;
 66    int res = -1 ;
 67    while (tail<=n)
 68    {
 69	int cur = rmq(head,tail);
 70	while (head<tail&&rmq(head,tail)>k) head++;
 71	while (tail<n&&rmq(head,tail)<m) tail++;
 72	//if (tail>n) break;
 73	cur = rmq(head,tail);
 74	if (cur>=m&&cur<=k)
 75	{
 76	    res = max(res,tail-head);
 77	}
 78//	cout<<"head:"<<head<<" tail:"<<tail<<" cur:"<<cur<<" res:"<<res<<endl;
 79	tail++;
 80
 81    }
 82    return res+1;
 83}
 84int main()
 85{
 86	#ifndef  ONLINE_JUDGE 
 87	freopen("code/in.txt","r",stdin);
 88  #endif
 89
 90	while (scanf("%d %d %d",&n,&m,&k)!=EOF)
 91	{
 92	    ms(dp,0);
 93	    for ( int i = 1 ; i  <= n ; i++) scanf("%d",&a[i]);
 94	    if (m>k)
 95	    {
 96		puts("0");
 97		continue;
 98	    }
 99	    rmq_init();
100	    printf("%d\n",ruler());
101	}
102
103
104
105  #ifndef ONLINE_JUDGE  
106  fclose(stdin);
107  #endif
108    return 0;
109}