最大和最小的 N 位八进制数

给定一个整数N ，任务是在八进制数系统中找到最小和最大的N 位数字。

例子：

Input: N = 4 
Output: 
Largest: 7777 
Smallest: 1000

Input: N = 2 
Output: 
Largest: 77 
Smallest: 10 

方法：可以按照以下步骤来计算所需的答案：

• 最大数：要得到最大数，该数的每一位都必须是最大值。八进制数系统中的最大位数是“ 7 ”。所以：

1 Digit Largest Number: '7'
2 Digit Largest Number: '77'
3 Digit Largest Number: '777'
                .
                .
                .
N Digit Largest Number: '777....(N) times'

• 最小数：八进制数中最小的数是“ 0 ”。这个想法是第一个数字需要尽可能小，除了 0 是 ‘1’ ，其余数字需要是0 。所以：

1 Digit Smallest Number: '1'
2 Digit Smallest Number: '10'
3 Digit Smallest Number: '100'
                .
                .
                .
N Digit Smallest Number: '100....(N - 1) times'

下面是上述方法的实现：

C++

// C++ program to find the largest
// and smallest N-digit numbers
// in Octal Number System
 
#include 
using namespace std;
 
// Function to return the largest
// N-digit number in Octal
// Number System
string findLargest(int N)
{
    // Append '7' N times
    string largest = string(N, '7');
 
    return largest;
}
 
// Function to return the smallest
// N-digit number in Octal
// Number System
string findSmallest(int N)
{
    // Append '0' (N - 1) times to 1
    string smallest
        = "1"
          + string((N - 1), '0');
 
    return smallest;
}
 
// Function to print the largest and
// smallest N-digit Octal number
void printLargestSmallest(int N)
{
    cout << "Largest: "
         << findLargest(N) << endl;
    cout << "Smallest: "
         << findSmallest(N) << endl;
}
 
// Driver code
int main()
{
    int N = 4;
 
    // Function Call
    printLargestSmallest(N);
 
    return 0;
}

Java

// Java program to find the largest
// and smallest N-digit numbers
// in Octal Number System
class GFG
{
  
// Function to return the largest
// N-digit number in Octal
// Number System
static String findLargest(int N)
{
    // Append '7' N times
    String largest = strings(N, '7');
  
    return largest;
}
  
// Function to return the smallest
// N-digit number in Octal
// Number System
static String findSmallest(int N)
{
    // Append '0' (N - 1) times to 1
    String smallest
        = "1"
          + strings((N - 1), '0');
  
    return smallest;
}
  
private static String strings(int N, char c) {
    String temp ="";
    for(int i= 0; i < N; i++) {
        temp+=c;
    }
    return temp;
}
 
// Function to print the largest and
// smallest N-digit Octal number
static void printLargestSmallest(int N)
{
    System.out.print("Largest: "
         + findLargest(N) +"\n");
    System.out.print("Smallest: "
         + findSmallest(N) +"\n");
}
  
// Driver code
public static void main(String[] args)
{
    int N = 4;
  
    // Function Call
    printLargestSmallest(N);
}
}
 
// This code is contributed by 29AjayKumar

Python3

# Python program to find the largest
# and smallest N-digit numbers
# in Octal Number System
 
# Function to return the largest
# N-digit number in Octal
# Number System
def findLargest(N):
 
    # Append '7' N times
    largest = strings(N, '7');
    return largest;
 
# Function to return the smallest
# N-digit number in Octal
# Number System
def findSmallest(N):
 
    # Append '0' (N - 1) times to 1
    smallest = "1" + strings((N - 1), '0');
    return smallest;
 
def strings(N, c):
    temp = "";
    for i in range(N):
        temp += c;
    return temp;
 
# Function to print the largest and
# smallest N-digit Octal number
def printLargestSmallest(N):
    print("Largest: ",findLargest(N));
    print("Smallest: ",findSmallest(N));
 
# Driver code
if __name__ == '__main__':
    N = 4;
 
    # Function Call
    printLargestSmallest(N);
 
# This code is contributed by sapnasingh4991

C#

// C# program to find the largest
// and smallest N-digit numbers
// in Octal Number System
using System;
 
class GFG
{
   
// Function to return the largest
// N-digit number in Octal
// Number System
static String findLargest(int N)
{
    // Append '7' N times
    String largest = strings(N, '7');
   
    return largest;
}
   
// Function to return the smallest
// N-digit number in Octal
// Number System
static String findSmallest(int N)
{
    // Append '0' (N - 1) times to 1
    String smallest
        = "1"
          + strings((N - 1), '0');
   
    return smallest;
}
   
private static String strings(int N, char c) {
    String temp ="";
    for(int i= 0; i < N; i++) {
        temp+=c;
    }
    return temp;
}
  
// Function to print the largest and
// smallest N-digit Octal number
static void printLargestSmallest(int N)
{
    Console.Write("Largest: "
         + findLargest(N) +"\n");
    Console.Write("Smallest: "
         + findSmallest(N) +"\n");
}
   
// Driver code
public static void Main(String[] args)
{
    int N = 4;
   
    // Function Call
    printLargestSmallest(N);
}
}
 
// This code is contributed by PrinciRaj1992

Javascript

 
// Javascript program to find the largest
// and smallest N-digit numbers
// in Octal Number System
 
// Function to return the largest
// N-digit number in Octal
// Number System
function findLargest(N)
{
    // Append '7' N times
    var largest = new Array(N+1).join( '7' );
    return largest;
}
 
// Function to return the smallest
// N-digit number in Octal
// Number System
function findSmallest(N)
{
    // Append '0' (N - 1) times to 1
    var smallest
        = "1"
          + new Array(N).join( '0' );
 
    return smallest;
}
 
// Function to print the largest and
// smallest N-digit Octal number
function printLargestSmallest(N)
{
    document.write("Largest: "
         + findLargest(N) + "<br>");
 
    document.write( "Smallest: "
         + findSmallest(N));
}
 
// Driver code
var N = 4;
// Function Call
printLargestSmallest(N);
 

输出：

Largest: 7777
Smallest: 1000

时间复杂度： O(N) ，其中 N 是字符串的长度。