HDU 6197 array array array(2017瀋陽テニス-最長上昇サブシーケンス)

タイトル:
n個の数を教えて、k個の数を除いたかどうかを聞いた後、元のシーケンスは非厳格な増加シーケンスまたは非厳格な減少シーケンスになります. 
考え方:
明らかに1回のLISを求めて、逆さまにして一方のLISを求めて、ansとkの関係を比較すればいいです.

#include 
#include 
#include 
using namespace std;
int T;

const int maxn = 100000 + 10;

int a[maxn], c[maxn];

int main(){
    scanf("%d",&T);
    while(T--){
        int n, k;
        scanf("%d %d",&n, &k);
        for (int i = 0; i < n; ++i){
            scanf("%d", a+i);
        }

        int cnt = 0;
        int ans = 0;
        for (int i = 0; i < n; ++i){

            int p = upper_bound(c, c + cnt, a[i]) - c;
            if (p == cnt){
                c[cnt++] = a[i];
                ans = max(ans, cnt);
            }
            else {
                c[p] = a[i];
            }
        }
        cnt = 0;
        for (int i = n-1; i >= 0; --i){
            int p = upper_bound(c, c + cnt, a[i]) - c;
            if (p == cnt){
                c[cnt++] = a[i];
                ans = max(ans, cnt);
            }
            else {
                c[p] = a[i];
            }
        }
//        printf("ans = %d
", ans);
        if (n - k <= ans){
            puts("A is a magic array.");
        }
        else {
            puts("A is not a magic array.");
        }


    }


    return 0;
}

array array array
Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others) Total Submission(s): 219    Accepted Submission(s): 131
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.
 
Source
2017 ACM/ICPC Asia Regional Shenyang Online
 
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