2017 ACM/ICPC Asia Regional Shenyang Online D

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 sayA 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 integersn 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

34 11 4 3 75 24 1 3 1 26 11 4 3 5 4 6

 

Sample Output

A is a magic array.A is a magic array.A is not a magic array.

 

类似于最长递增子序列

正方来一次，反向来一次。

#include <bits/stdc++.h>using namespace std;const int MAXN = 1e5+10;int a[MAXN];int b[MAXN];int t[MAXN];int len1,len2;int main(){    int T,n,k;    scanf("%d",&T);    while(T--)    {        memset(b,0,sizeof(b));        scanf("%d %d",&n,&k);        for(int i = 0; i < n; ++i)        {            scanf("%d",&a[i]);            t[n-i-1] = a[i];        }        b[1] = a[0];        int len = 1,j;        for(int i = 1; i < n; ++i)        {            if(a[i] >= b[len])                b[++len] = a[i];            else            {                j = lower_bound(b+1,b+1+len,a[i])-b;                b[j] = a[i];            }        }        len1 = n-len;        memset(b,0,sizeof(b));        b[1] = t[0];        len = 1;        for(int i = 1; i < n; ++i)        {            if(t[i] >= b[len])                b[++len] = t[i];            else            {                j = lower_bound(b+1,b+1+len,t[i])-b;                b[j] = t[i];            }        }        len2 = n-len;        if(k >= len1 || k >= len2)            printf("A is a magic array.\n");        else            printf("A is not a magic array.\n");    }    return 0;}