使用cpp查找数组中素数个数的程序

Question

函数 prime 中的问题，但它认为是真的，我找不到解决方案

我在 codeforces 中提交了它，但它给了我。测试 5 的错误答案
:-

输入：

39
81 46 4 5 2 71 66 97 51 84 50 64 68 99 58 45 64 86 14 44 7 49 45 72 94 19 33 68 83 12 89 88 39 36 51 11 57 9 54

the wrong !!

#include <iostream>
#include <math.h>
using namespace std;
int maximum(int arr[], int n)
{
    int max = INT_MIN;
    for (int i = 0; i < n; i++)
    {
        if (max < arr[i]) { max = arr[i]; }
    }
    return max;
}
int minimum(int arr[], int n)
{
    int min = INT_MAX;
    for (int i = 0; i < n; i++)
    {
        if (min > arr[i]) { min = arr[i]; }
    }
    return min;
}
int prime(int arr[], int n)
{
    int con = 0;
    bool flag = true;
    for (int i = 0; i < n; i++)
    {
        if (arr[i] == 2)
        {
            con++;
        }
        else if (arr[i] > 2)
        {
            for (int j = 2; j < n; j++)
            {
                if (arr[i] % j == 0)
                {
                    flag = false;
                    break;
                }
                else
                {
                    flag = true;
                }
            }
            if (flag == true)
                con++;
        }
    }

    return con;

}
int palindrome(int arr[], int n)
{
    int i = 0, con = 0;
    while (n--)
    {
        int temp;
        temp = arr[i];
        int reverseNumber = 0, rightDigit;
        while (temp != 0)
        {
            rightDigit = temp % 10;
            reverseNumber = (reverseNumber * 10) + rightDigit;
            temp = temp / 10;
        }
        if (reverseNumber == arr[i]) {
            con++;
        }
        i++;

    }
    return con;
}
int divisors(int arr[], int n)
{
    int max = 0;
    int con = 0;
    int x = arr[0];
    for (int i = 0; i < n; i++)
    {
        int temp = arr[i];
        for (int j = 1; j <= arr[i]; j++)
        {
            if (arr[i] % j == 0)
            {
                con++;
            }
        }
        if (max < con)
        {
            max = con;
            x = arr[i];
        }
        else if (max == con)
        {
            if (x < arr[i])
            {
                x = arr[i];
            }
        }

        con = 0;
    }
    return x;
}
int main()
{
    int n; cin >> n;
    int arr[1001];
    for (int i = 0; i < n; i++)
        cin >> arr[i];
    cout << "The maximum number : " << maximum(arr, n) << endl;
    cout << "The minimum number : " << minimum(arr, n) << endl;
    cout << "The number of prime numbers : " << prime(arr, n) << endl;
    cout << "The number of palindrome numbers : " << palindrome(arr, n) << endl;
    cout << "The number that has the maximum number of divisors : " << divisors(arr, n) << endl;
    divisors(arr, n);
    return 0;
}

Answer 1

这个for循环

for (int j = 2; j < n; j++)

不正确。看来你的意思是

for (int j = 2; j < arr[i]; j++)

您还应该在使用它的 else 语句中声明变量标志。例如

for (int i = 0; i < n; i++)
{
    if (arr[i] == 2)
    {
        con++;
    }
    else if (arr[i] > 2)
    { 
        bool flag = false;
        //...

使用cpp查找数组中素数个数的程序

program to find The number of prime numbers in array using cpp

c++

arrays

for-loop

primes

function-definition