检查数字 N 的第一位和最后一位是否为素数并且它们的和小于 K
给定一个数字 N，任务是检查它的第一个和最后一个数字是否是质数，并且它们的和是否小于 K。如果是，则打印 Yes，否则打印 No。
例子：
Input: N = 322223, K = 10
Output: Yes
Input: N = 62531561, K = 15
Output: No方法：
- 检查 N 的第一个和最后一个数字是否为质数。
- 如果它们是素数，则检查它们是否小于 K
- 如果它们也小于 K，则打印 Yes。
- 在任何其他情况下，打印 No。
下面是上述方法的实现：
C++
// C++ program to check
// if the first and last digit of number N
// is prime and their sum is less than K
#include
using namespace std;
// Get the First digit of the number
int first(int n)
{
int a = n;
int c = 1;
while (a != 0)
{
a /= 10;
c = c * 10;
}
c = c / 10;
int fi = n / c;
return fi;
}
// Check if the digit is prime or not
bool prime(int n)
{
switch (n)
{
case 2:
return true;
case 3:
return true;
case 5:
return true;
case 7:
return true;
default:
return false;
}
}
// Function to Check if the first
// and last digit of number N is prime
// and their sum is less than K
void check(int n, int k)
{
// Last digit of the number
int l = n % 10;
// First digit of number
int f = first(n);
// Check if these are prime
bool lp = prime(l);
bool fp = prime(f);
// If they are prime
if (lp && fp)
{
// Check if they are less than k or not
if (l + f < k)
cout << "Yes\n";
else
cout << "No\n";
}
else
{
cout << "No\n";
}
}
// Driver code
int main()
{
// Test case 1
int n = 322223;
int k = 10;
check(n, k);
// Test case 2
n = 62531561;
k = 15;
check(n, k);
return 0;
}
// This code is contributed by PrinciRaj1992 Java
// Java program to check
// if the first and last digit of number N
// is prime and their sum is less than K
import java.lang.*;
public class crazy_number {
// Get the First digit of the number
public static int first(int n)
{
int a = n;
int c = 1;
while (a != 0) {
a /= 10;
c = c * 10;
}
c = c / 10;
int fi = n / c;
return fi;
}
// Check if the digit is prime or not
public static boolean prime(int n)
{
switch (n) {
case 2:
return true;
case 3:
return true;
case 5:
return true;
case 7:
return true;
default:
return false;
}
}
// Function to Check if the first
// and last digit of number N is prime
// and their sum is less than K
public static void check(int n, int k)
{
// Last digit of the number
int l = n % 10;
// First digit of number
int f = first(n);
// Check if these are prime
boolean lp = prime(l);
boolean fp = prime(f);
// If they are prime
if (lp && fp) {
// Check if they are less than k or not
if (l + f < k)
System.out.println("Yes");
else
System.out.println("No");
}
else {
System.out.println("No");
}
}
// Driver code
public static void main(String args[])
{
// Test case 1
int n = 322223;
int k = 10;
check(n, k);
// Test case 2
n = 62531561;
k = 15;
check(n, k);
}
}Python3
# Python3 program to check if
# the first and last digit of number N
# is prime and their sum is less than K
# Get the First digit of the number
def first(n):
a = n
c = 1
while (a != 0):
a //= 10
c = c * 10
c = c // 10
fi = n // c
return fi
# Check if the digit is prime or not
def prime(n):
if n in [2, 3, 5, 7]:
return True
else:
return False
# Function to Check if the first
# and last digit of number N is prime
# and their sum is less than K
def check(n, k):
# Last digit of the number
l = n % 10
# First digit of number
f = first(n)
# Check if these are prime
lp = prime(l)
fp = prime(f)
# If they are prime
if (lp and fp):
# Check if they are less than k or not
if (l + f < k):
print("Yes")
else:
print("No")
else:
print("No")
# Driver code
# Test case 1
n = 322223
k = 10
check(n, k)
# Test case 2
n = 62531561
k = 15
check(n, k)
# This code is contributed by Mohit kumarC#
// C# program to check
// if the first and last digit of number N
// is prime and their sum is less than K
using System;
class GFG
{
// Get the First digit of the number
public static int first(int n)
{
int a = n;
int c = 1;
while (a != 0)
{
a /= 10;
c = c * 10;
}
c = c / 10;
int fi = n / c;
return fi;
}
// Check if the digit is prime or not
public static Boolean prime(int n)
{
switch (n)
{
case 2:
return true;
case 3:
return true;
case 5:
return true;
case 7:
return true;
default:
return false;
}
}
// Function to Check if the first
// and last digit of number N is prime
// and their sum is less than K
public static void check(int n, int k)
{
// Last digit of the number
int l = n % 10;
// First digit of number
int f = first(n);
// Check if these are prime
Boolean lp = prime(l);
Boolean fp = prime(f);
// If they are prime
if (lp && fp)
{
// Check if they are less than k or not
if (l + f < k)
Console.WriteLine("Yes");
else
Console.WriteLine("No");
}
else
{
Console.WriteLine("No");
}
}
// Driver code
public static void Main(String []args)
{
// Test case 1
int n = 322223;
int k = 10;
check(n, k);
// Test case 2
n = 62531561;
k = 15;
check(n, k);
}
}
// This code is contributed by PrinciRaj1992Javascript
输出：
Yes
No