【2017 ACM/ICPC Asia Regional Shenyang Online 1004】hdu 6197 array array array

array array array

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 431    Accepted Submission(s): 269

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.

 

题意：给你一个长度为n的序列，你可以删除m个元素，使得这个序列变成一个单调上升或下降序列。
思路：就是求最长上升或下降子序列长度是不是大于n-k

#include <iostream>#include <cstring>#include <cmath>#include <cstdio>#include <algorithm>#define N 100010using namespace std;const long long mod = 1000000007;int numb[N], dp[N], numa[N];int BiSearch(int len, int key)  //二分法{    int l = 0, r = len - 1;    while (l <= r)    {        int mid = (l + r) / 2;        if (dp[mid] > key)        {            r = mid - 1;        }        else if (dp[mid] < key)        {            l = mid + 1;        }        else        {            return mid;        }    }    return l;}int main(){    cin.sync_with_stdio(false);    int n, m, T;    cin >> T;    while (T--)    {        cin >> n >> m;        for (int i = 0; i < n; i++)        {            cin >> numa[i];            numb[i] = -numa[i];        }        int len = 1;        dp[0] = numa[0];        for (int i = 1; i < n; i++)        {            if (numa[i] > dp[len - 1])            {                dp[len] = numa[i];                len++;            }            else            {                int pos = BiSearch(len, numa[i]);                dp[pos] = numa[i];            }        }        int lena = len;        len = 1;        dp[0] = numb[0];        for (int i = 1; i < n; i++)        {            if (numb[i] > dp[len - 1])            {                dp[len] = numb[i];                len++;            }            else            {                int pos = BiSearch(len, numb[i]);                dp[pos] = numb[i];            }        }        int lenb = len;        if (n == m || n - m <= lena || n - m <= lenb)        {            cout << "A is a magic array." << endl;        }        else        {            cout << "A is not a magic array." << endl;        }    }    return 0;}