可被X整除的最大K位数字

给出了整数X和K。任务是找到可被X整除的最高K位数字。
例子：

Input : X = 30, K = 3
Output : 990
990 is the largest three digit 
number divisible by 30.

Input : X = 7, K = 2
Output : 98

一个简单的解决方案是尝试从最大的K位数字(即999…K次)开始的所有数字，然后返回第一个可被X整除的数字。
一个有效的解决方案是使用以下公式。

ans = MAX - (MAX % X)
where MAX is the largest K digit 
number which is  999...K-times

该公式适用于简单的学校方法划分。我们删除余数以得到最大的可除数。

C++

// CPP code to find highest K-digit number divisible by X
#include 
using namespace std;
 
// Function to compute the result
int answer(int X, int K)
{
    // Computing MAX
    int MAX = pow(10, K) - 1;
 
    // returning ans
    return (MAX - (MAX % X));
}
 
// Driver
int main()
{
    // Number whose divisible is to be found
    int X = 30;
 
    // Max K-digit divisible is to be found
    int K = 3;
 
    cout << answer(X, K);
}

Java

// Java code to find highest
// K-digit number divisible by X
 
import java.io.*;
import java.lang.*;
 
class GFG {
    public static double answer(double X, double K)
    {
        double i = 10;
        // Computing MAX
        double MAX = Math.pow(i, K) - 1;
 
        // returning ans
        return (MAX - (MAX % X));
    }
 
    public static void main(String[] args)
    {
 
        // Number whose divisible is to be found
        double X = 30;
 
        // Max K-digit divisible is to be found
        double K = 3;
 
        System.out.println((int)answer(X, K));
    }
}
 
// Code contributed by Mohit Gupta_OMG <(0_o)>

Python3

# Python code to find highest
# K-digit number divisible by X
 
def answer(X, K):
     
    # Computing MAX
    MAX = pow(10, K) - 1
     
    # returning ans
    return (MAX - (MAX % X))
 
X = 30;
K = 3;
 
print(answer(X, K));
 
# Code contributed by Mohit Gupta_OMG <(0_o)>

C#

// C# code to find highest
// K-digit number divisible by X
 
using System;
 
class GFG {
     
    public static double answer(double X, double K)
    {
         
        double i = 10;
         
        // Computing MAX
        double MAX = Math.Pow(i, K) - 1;
 
        // returning ans
        return (MAX - (MAX % X));
    }
 
    public static void Main()
    {
 
        // Number whose divisible is to be found
        double X = 30;
 
        // Max K-digit divisible is to be found
        double K = 3;
 
        Console.WriteLine((int)answer(X, K));
    }
}
 
// This code is contributed by vt_m.

Javascript

// Javascript code to find highest K-digit
// number divisible by X
 
// Function to compute the result
function answer(X, K)
{
     
    // Computing MAX
    let MAX = Math.pow(10, K) - 1;
 
    // returning ans
    return (MAX - (MAX % X));
}
 
// Driver
    // Number whose divisible
    // is to be found
    let X = 30;
 
    // Max K-digit divisible
    // is to be found
    let K = 3;
 
    document.write(answer(X, K));
 
// This code is contributed by gfgking

输出：

990