HDU6197-array array array

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最新推荐文章于 2024-06-29 00:50:45 发布

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本文介绍了一个编程问题，即判断一个数组是否为“魔法数组”。通过删除k个元素后，检查剩余数组是否为非严格单调递增或递减序列。文章提供了完整的代码实现，并解释了解决方案的思路。

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array array array

Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 727 Accepted Submission(s): 421

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

题意：给你一个序列，问去掉k个数后，这个序列能否使非严格单调递增或递减的

解题思路：求出这个序列最长的非严格单调递增或递减的序列长度即可

#include <iostream>
#include <cstdio>
#include <cstring>
#include <string>
#include <algorithm>
#include <cmath>
#include <map>
#include <cmath>
#include <set>
#include <stack>
#include <queue>
#include <vector>
#include <bitset>
#include <functional>

using namespace std;

#define LL long long
const int INF = 0x3f3f3f3f;

int n,k, a[100009],b[100009];

int main()
{
    int t;
    scanf("%d", &t);
    while (t--)
    {
        scanf("%d %d", &n,&k);
        for (int i = 1; i <= n; i++) scanf("%d", &a[i]);
        int cnt = 0, ans = 0;
        for (int i = 1; i <= n; i++)
        {
            int p = upper_bound(b, b + cnt, a[i]) - b;
            if (p == cnt) { b[cnt++] = a[i], ans = max(ans, cnt); }
            else b[p] = a[i];
        }
        cnt = 0;
        for (int i = n; i >= 1; i--)
        {
            int p = upper_bound(b, b + cnt, a[i]) - b;
            if (p == cnt) { b[cnt++] = a[i], ans = max(ans, cnt); }
            else b[p] = a[i];
        }
        if (k + ans >= n) printf("A is a magic array.\n");
        else printf("A is not a magic array.\n");
    }
    return 0;
}