【HDU 6197】array array array 【LIS】

Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 2917 Accepted Submission(s): 1170

Problem Description
One day, Kaitou Kiddo had stolen a priceless diamond ring. But detective Conan blocked Kiddo’s path to escape from the museum. But Kiddo didn’t want to give it back. So, Kiddo asked Conan a question. If Conan could give a right answer, Kiddo would return the ring to the museum.
Kiddo: “I have an array A and a number k, if you can choose exactly k elements from A and erase them, then the remaining array is in non-increasing order or non-decreasing order, we say A is a magic array. Now I want you to tell me whether A is a magic array. ” Conan: “emmmmm…” Now, Conan seems to be in trouble, can you help him?

Input
The first line contains an integer T indicating the total number of test cases. Each test case starts with two integers n and k in one line, then one line with n integers: A1,A2…An.
1≤T≤20
1≤n≤105
0≤k≤n
1≤Ai≤105

Output
For each test case, please output “A is a magic array.” if it is a magic array. Otherwise, output “A is not a magic array.” (without quotes).

Sample Input
3
4 1
1 4 3 7
5 2
4 1 3 1 2
6 1
1 4 3 5 4 6

Sample Output
A is a magic array.
A is a magic array.
A is not a magic array.

题意 给一个序列，你有k个权利【可以用来删除其中的k个数】，使其处理过后的序列为非减或者非增序列。 问是否成功。
最后的结果为非减或者非增，我们可以联想到LIS ，非减为LIS，非增我们可以吧序列反过来，然后再跑一遍LIS。如果 k+ len >=n 就可以成功。
代码

#include<bits/stdc++.h>using namespace std ;typedef long long LL ;const int MAXN = 1e5+10;const int MAXM = 1e5 ;const int mod  = 1e9+7 ;int arr[MAXN];int brr[MAXN];int dp[MAXN];int main(){    int t;scanf("%d",&t);    while(t--){        int n,k;scanf("%d%d",&n,&k);        for(int i=1;i<=n;i++) scanf("%d",&arr[i]);        dp[1]=arr[1];int top=1;        for(int i=2;i<=n;i++){            if(arr[i]>=dp[top]) dp[++top]=arr[i];            else {                int pos=lower_bound(dp,dp+top,arr[i])-dp;                dp[pos]=arr[i];            }        }        if(top+k>=n) puts("A is a magic array.");        else {            int j=n;            for(int i=1;i<=n;i++)   brr[j--]=arr[i];            dp[1]=brr[1];  top=1;        for(int i=2;i<=n;i++){            if(brr[i]>=dp[top]) dp[++top]=brr[i];            else {                int pos=lower_bound(dp,dp+top,brr[i])-dp;                dp[pos]=brr[i];            }        }        if(top+k>=n) puts("A is a magic array.");        else puts("A is not a magic array.");    }}    return 0;}