hdu 6197 贪心 最长单调递增子序列

array array array

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)

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

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.

 

Source

2017 ACM/ICPC Asia Regional Shenyang Online

题意很绕口。

n长序列，n-k 长的子序列能否严格单调上升（或下降）

严格单调上升（或下降）子序列的长度 >=n-k 就满足

import java.io.BufferedReader;import java.io.InputStream;import java.io.InputStreamReader;import java.io.PrintWriter;import java.math.BigInteger;import java.util.StringTokenizer;public class Main {        public static void main(String[] args) {        new Task().solve();    }}class Task {    InputReader in = new InputReader(System.in) ;    PrintWriter out = new PrintWriter(System.out) ;           void solve(){        int t = in.nextInt() ;        while(t-- > 0){            int n = in.nextInt() ;            int k = in.nextInt() ;            int[] arr = new int[n+1] ;            for(int i = 1 ; i <= n ; i++){                arr[i] = in.nextInt() ;             }            int[] ord = new int[n+1] ;            int top = 0 ;            ord[++top] = arr[1] ;            for(int i = 2 ; i <= n ; i++){                int l = 1 , r = top , mid , s = -1 ;                while(l <= r){                    mid = (l + r) >> 1 ;                    if(ord[mid] >= arr[i]){                        s = mid ;                        r = mid - 1 ;                    }                    else{                        l = mid + 1 ;                    }                }                if(s == -1){                    ord[++top] = arr[i] ;                }                else{                    ord[s] = arr[i] ;                }            }            if(top >= n-k){                out.println("A is a magic array.") ;                continue ;            }            else{                top = 0 ;                ord[++top] = arr[n] ;                for(int i = n-1 ; i >= 1 ; i--){                    int l = 1 , r = top , mid , s = -1 ;                    while(l <= r){                        mid = (l + r) >> 1 ;                        if(ord[mid] >= arr[i]){                            s = mid ;                            r = mid - 1 ;                        }                        else{                            l = mid + 1 ;                        }                    }                    if(s == -1){                        ord[++top] = arr[i] ;                    }                    else{                        ord[s] = arr[i] ;                    }                }                if(top >= n-k){                    out.println("A is a magic array.") ;                }                else{                    out.println("A is not a magic array.") ;                }            }        }        out.flush() ;    }}class InputReader {        public BufferedReader reader;        public StringTokenizer tokenizer;            public InputReader(InputStream stream) {            reader = new BufferedReader(new InputStreamReader(stream), 32768);            tokenizer = new StringTokenizer("");        }        private void eat(String s) {            tokenizer = new StringTokenizer(s);        }            public String nextLine() {             try {                return reader.readLine();            } catch (Exception e) {                return null;            }        }            public boolean hasNext() {            while (!tokenizer.hasMoreTokens()) {                String s = nextLine();                if (s == null)                    return false;                eat(s);            }            return true;        }            public String next() {            hasNext();            return tokenizer.nextToken();        }            public int nextInt() {            return Integer.parseInt(next());        }            public int[] nextInts(int n) {            int[] nums = new int[n];            for (int i = 0; i < n; i++) {                nums[i] = nextInt();            }            return nums;        }            public long nextLong() {            return Long.parseLong(next());        }            public double nextDouble() {            return Double.parseDouble(next());        }            public BigInteger nextBigInteger() {            return new BigInteger(next());        }        }