codeforces680C

本文介绍了一个通过互动查询来判断隐藏数字是否为质数的算法。该算法允许最多进行20次查询,每次查询需从2到100中选择一个整数并询问其是否为隐藏数字的因数。根据系统反馈,最终确定隐藏数字是质数还是合数。

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C. Bear and Prime 100
time limit per test
1 second
memory limit per test
256 megabytes
input
standard input
output
standard output

This is an interactive problem. In the output section below you will see the information about flushing the output.

Bear Limak thinks of some hidden number — an integer from interval [2, 100]. Your task is to say if the hidden number is prime or composite.

Integer x > 1 is called prime if it has exactly two distinct divisors, 1 and x. If integer x > 1 is not prime, it's called composite.

You can ask up to 20 queries about divisors of the hidden number. In each query you should print an integer from interval [2, 100]. The system will answer "yes" if your integer is a divisor of the hidden number. Otherwise, the answer will be "no".

For example, if the hidden number is 14 then the system will answer "yes" only if you print 2, 7 or 14.

When you are done asking queries, print "prime" or "composite" and terminate your program.

You will get the Wrong Answer verdict if you ask more than 20 queries, or if you print an integer not from the range [2, 100]. Also, you will get the Wrong Answer verdict if the printed answer isn't correct.

You will get the Idleness Limit Exceeded verdict if you don't print anything (but you should) or if you forget about flushing the output (more info below).

Input

After each query you should read one string from the input. It will be "yes" if the printed integer is a divisor of the hidden number, and "no" otherwise.

Output

Up to 20 times you can ask a query — print an integer from interval [2, 100] in one line. You have to both print the end-of-line character and flush the output. After flushing you should read a response from the input.

In any moment you can print the answer "prime" or "composite" (without the quotes). After that, flush the output and terminate your program.

To flush you can use (just after printing an integer and end-of-line):

  • fflush(stdout) in C++;
  • System.out.flush() in Java;
  • stdout.flush() in Python;
  • flush(output) in Pascal;
  • See the documentation for other languages.

Hacking. To hack someone, as the input you should print the hidden number — one integer from the interval [2, 100]. Of course, his/her solution won't be able to read the hidden number from the input.

Examples
Input
yes
no
yes
Output
2
80
5
composite
Input
no
yes
no
no
no
Output
58
59
78
78
2
prime
Note

The hidden number in the first query is 30. In a table below you can see a better form of the provided example of the communication process.

The hidden number is divisible by both 2 and 5. Thus, it must be composite. Note that it isn't necessary to know the exact value of the hidden number. In this test, the hidden number is 30.

59 is a divisor of the hidden number. In the interval [2, 100] there is only one number with this divisor. The hidden number must be 59, which is prime. Note that the answer is known even after the second query and you could print it then and terminate. Though, it isn't forbidden to ask unnecessary queries (unless you exceed the limit of 20 queries).

#include <bits/stdc++.h>
using namespace std;
const int MAX = 100;
char s[5];
bool isPrime(int a){
    for(int i = 2;i * i <= a;i++){
        if(a%i==0) return false;
    }
    return true;
}
bool can(int a){
    printf("%d\n", a);
    fflush(stdout);
    scanf("%s", s);
    return s[0]=='y';
}
int main()
{
    int cnt = 0;
    for(int i = 2;i <= MAX/2&&cnt<2;i++){
        if(isPrime(i)){
            if(can(i)){
                cnt++;
                if(i*i<=MAX&&can(i*i)) cnt++;
            }
        }
    }
    printf("%s\n", cnt>=2?"composite":"prime");
}

### Codeforces Problem 1332C Explanation The provided references pertain specifically to problem 742B on Codeforces rather than problem 1332C. For an accurate understanding and solution approach for problem 1332C, it's essential to refer directly to its description and constraints. However, based on general knowledge regarding competitive programming problems found on platforms like Codeforces: Problem 1332C typically involves algorithmic challenges that require efficient data structures or algorithms such as dynamic programming, graph theory, greedy algorithms, etc., depending upon the specific nature of the task described within this particular question[^6]. To provide a detailed explanation or demonstration concerning **Codeforces problem 1332C**, one would need direct access to the exact statement associated with this challenge since different tasks demand tailored strategies addressing their unique requirements. For obtaining precise details about problem 1332C including any sample inputs/outputs along with explanations or solutions, visiting the official Codeforces website and navigating to contest number 1332 followed by examining section C is recommended. ```python # Example pseudo-code structure often seen in solving competitive coding questions. def solve_problem_1332C(input_data): # Placeholder function body; actual logic depends heavily on the specifics of problem 1332C. processed_result = process_input(input_data) final_answer = compute_solution(processed_result) return final_answer input_example = "Example Input" print(solve_problem_1332C(input_example)) ```
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