HDU5489 LIS变形

Removed Interval

Problem Description

Given a sequence of numbers A=a1,a2,…,aN

, a subsequence b1,b2,…,bk

of A

is referred as increasing if b1<b2<…<bk

. LY has just learned how to find the longest increasing subsequence (LIS).
Now that he has to select L

consecutive numbers and remove them from A

for some mysterious reasons. He can choose arbitrary starting position of the selected interval so that the length of the LIS of the remaining numbers is maximized. Can you help him with this problem?

 

Input

The first line of input contains a number T

indicating the number of test cases (T≤100

).
For each test case, the first line consists of two numbers N

and L

as described above (1≤N≤100000,0≤L≤N

). The second line consists of N

integers indicating the sequence. The absolute value of the numbers is no greater than 109

.
The sum of N over all test cases will not exceed 500000.

 

Output

For each test case, output a single line consisting of “Case #X: Y”. X

is the test case number starting from 1. Y

is the maximum length of LIS after removing the interval.

 

Sample Input

2
5 2
1 2 3 4 5
5 3
5 4 3 2 1

 

Sample Output

Case #1: 3
Case #2: 1

 

题意：一个含有n个元素的数组，删去k个连续数后，求LIS

题解：定义l[i]为  以第i个数结尾，删除i-k-1到i-1这k个数的LIS

        定义r[i]为 以i开头到n的LIS

       因为这样我们会忽略删除最后K个数的情况，所以我们n+1   最后一个元素赋值为无穷大

       答案就是 l[i]+r[i]-2;

///

#include<bits/stdc++.h>
using namespace std;
//#pragma comment(linker, "/STACK:102400000,102400000")
using namespace std ;
typedef long long ll;
#define mem(a) memset(a,0,sizeof(a))
#define pb push_back
inline ll read()
{
    ll x=,f=;char ch=getchar();
    while(ch<''||ch>''){
        if(ch=='-')f=-;ch=getchar();
    }
    while(ch>=''&&ch<=''){
        x=x*+ch-'';ch=getchar();
    }return x*f;
}
//****************************************
const int  N=+;
#define mod 1000000007
#define inf 1000000007

int b[N],a[N],dp[N],l[N],r[N],n,L;

int main() {
  int T=read();int oo=;
  while(T--) {
     mem(a),mem(b);
     scanf("%d%d",&n,&L);
     for(int i=;i<=n;i++) {
        scanf("%d",&a[i]);
     }a[++n]=inf;
     for(int i=;i<=n;i++) {
        b[n-i+]=-a[i];
     }
     fill(dp+,dp+n+,inf+);
     for(int i=L+;i<=n;i++) {
        int tmp=lower_bound(dp+,dp+n+,a[i])-dp;
        l[i]=tmp;
        tmp=lower_bound(dp+,dp+n+,a[i-L])-dp;
        dp[tmp]=a[i-L];
     }
     fill(dp+,dp+n+,inf);
     for(int i=;i<=n;i++) {
        int tmp=lower_bound(dp+,dp+n+,b[i])-dp;
        r[n-i+]=tmp;
        dp[tmp]=b[i];
     }
     //for(int i=1;i<=n;i++)cout<< l[i]<<" ";
     //cout<<endl;
     //for(int i=1;i<=n;i++)cout<< r[i]<<" ";
     int ans=;
     for(int i=L+;i<=n;i++) {
        ans=max(ans,l[i]+r[i]-);
     }
     printf("Case #%d: ",oo++);
     cout<<ans<<endl;
  }
  return ;
}

代码