不使用任何循环打印图案
给定一个数字 n，按照一个模式打印，不使用任何循环。
示例:
Input: n = 16
Output: 16, 11, 6, 1, -4, 1, 6, 11, 16
Input: n = 10
Output: 10, 5, 0, 5, 10
我们基本上首先一个接一个地减少 5，直到达到负值或 0。达到 0 或负数后，再加一个 5，直到达到 n. 来源:微软面试问题。
我们强烈建议您点击此处进行练习，然后再进入解决方案。
想法是使用递归。这是一个自己尝试的有趣问题。 下面是代码。代码使用一个标志变量来指示我们是向 0 前进还是向 n 后退。
C++
// C++ program to print pattern that first reduces 5 one
// by one, then adds 5\. Without any loop
#include <iostream>
using namespace std;
// Recursive function to print the pattern.
// n indicates input value
// m indicates current value to be printed
// flag indicates whether we need to add 5 or
// subtract 5\. Initially flag is true.
void printPattern(int n, int m, bool flag)
{
// Print m.
cout << m << " ";
// If we are moving back toward the n and
// we have reached there, then we are done
if (flag == false && n ==m)
return;
// If we are moving toward 0 or negative.
if (flag)
{
// If m is greater, then 5, recur with true flag
if (m-5 > 0)
printPattern(n, m-5, true);
else // recur with false flag
printPattern(n, m-5, false);
}
else // If flag is false.
printPattern(n, m+5, false);
}
// Recursive function to print the pattern
// variance where m is the input int32 value
void PrintPattern(int m)
{
if (m > 0)
{
cout << m << '\n';
PrintPattern(m - 5);
}
cout << m << '\n';
}
// Driver Program
int main()
{
int n = 16;
//printPattern(n, n, true);
PrintPattern(n);
return 0;
}
Java 语言(一种计算机语言，尤用于创建网站)
// Java program to print pattern that first reduces 5 one
// by one, then adds 5\. Without any loop
import java.io.*;
class GFG {
// Recursive function to print the pattern.
// n indicates input value
// m indicates current value to be printed
// flag indicates whether we need to add 5 or
// subtract 5\. Initially flag is true.
static void printPattern(int n, int m, boolean flag)
{
// Print m.
System.out.print(m + " ");
// If we are moving back toward the n and
// we have reached there, then we are done
if (flag == false && n == m)
return;
// If we are moving toward 0 or negative.
if (flag) {
// If m is greater, then 5, recur with
// true flag
if (m - 5 > 0)
printPattern(n, m - 5, true);
else // recur with false flag
printPattern(n, m - 5, false);
}
else // If flag is false.
printPattern(n, m + 5, false);
}
// Driver Program
public static void main(String[] args)
{
int n = 16;
printPattern(n, n, true);
}
}
// This code is contributed by vt_m
Python 3
# Python program to print pattern
# that first reduces 5 one by one,
# then adds 5\. Without any loop.
# Recursive function to print
# the pattern.n indicates
# input value m indicates
# current value to be printed
# flag indicates whether we
# need to add 5 or subtract 5.
# Initially flag is True.
def printPattern(n, m, flag):
# Print m.
print(m)
# If we are moving back
# toward the n and we
# have reached there,
# then we are done
if flag == False and n == m:
return
# If we are moving
# toward 0 or negative.
if flag:
# If m is greater, then 5,
# recur with true flag
if m - 5 > 0:
printPattern(n, m - 5, True)
else: # recur with false flag
printPattern(n, m - 5, False)
else: # If flag is false.
printPattern(n, m + 5, False)
# Driver Code
n = 16
printPattern(n, n, True)
# This code is contributed
# by HrushikeshChoudhary
C
// C# program to print pattern that first reduces 5 one
// by one, then adds 5\. Without any loop
using System;
class GFG {
// Recursive function to print the pattern.
// n indicates input value
// m indicates current value to be printed
// flag indicates whether we need to add 5 or
// subtract 5\. Initially flag is true.
static void printPattern(int n, int m, bool flag)
{
// Print m.
Console.Write(m + " ");
// If we are moving back toward the n and
// we have reached there, then we are done
if (flag == false && n == m)
return;
// If we are moving toward 0 or negative.
if (flag) {
// If m is greater, then 5, recur with
// true flag
if (m - 5 > 0)
printPattern(n, m - 5, true);
else // recur with false flag
printPattern(n, m - 5, false);
}
else // If flag is false.
printPattern(n, m + 5, false);
}
// Driver Program
public static void Main()
{
int n = 16;
printPattern(n, n, true);
}
}
// This code is contributed by vt_m
服务器端编程语言（Professional Hypertext Preprocessor 的缩写）
<?php
// PHP program to print pattern
// that first reduces 5 one by one,
// then adds 5\. Without any loop
// Recursive function to print
// the pattern. n indicates input
// value m indicates current value
// to be printed flag indicates whether
// we need to add 5 or subtract 5.
// Initially flag is true.
function printPattern($n, $m, $flag)
{
// Print m.
echo $m ," ";
// If we are moving back
// toward the n and we
// have reached there,
// then we are done
if ($flag == false && $n == $m)
return;
// If we are moving
// toward 0 or negative.
if ($flag)
{
// If m is greater, then 5,
// recur with true flag
if ($m - 5 > 0)
printPattern($n, $m - 5, true);
// recur with false flag
else
printPattern($n, $m - 5, false);
}
// If flag is false.
else
printPattern($n, $m + 5, false);
}
// Driver Code
$n = 16;
printPattern($n, $n, true);
// This code is contributed by m_kit
?>
java 描述语言
<script>
// Javascript program to print pattern that
// first reduces 5 one by one, then adds 5.
// Without any loop
// Recursive function to print the pattern.
// n indicates input value m indicates current
// value to be printed flag indicates whether
// we need to add 5 or subtract 5\. Initially
// flag is true.
function printPattern(n, m, flag)
{
// Print m.
document.write(m + " ");
// If we are moving back toward the n and
// we have reached there, then we are done
if (flag == false && n == m)
return;
// If we are moving toward 0 or negative.
if (flag)
{
// If m is greater, then 5, recur with
// true flag
if (m - 5 > 0)
printPattern(n, m - 5, true);
// Recur with false flag
else
printPattern(n, m - 5, false);
}
// If flag is false.
else
printPattern(n, m + 5, false);
}
// Driver code
let n = 16;
printPattern(n, n, true);
// This code is contributed by divyeshrabadiya07
</script>
输出:
16, 11, 6, 1, -4, 1, 6, 11, 16
如何在没有任何额外变量和循环的情况下打印上述图案？ 上述程序运行良好，打印出所需的输出，但使用了额外的变量。我们可以使用两个打印语句。打印所有递减序列的递归调用之前的第一个。递归调用打印递增序列后的第二个。
下面是这个想法的实现。
C++
// C++ program to print pattern that first reduces 5 one
// by one, then adds 5\. Without any loop an extra variable.
#include <iostream>
using namespace std;
// Recursive function to print the pattern without any extra
// variable
void printPattern(int n)
{
// Base case (When n becomes 0 or negative)
if (n ==0 || n<0)
{
cout << n << " ";
return;
}
// First print decreasing order
cout << n << " ";
printPattern(n-5);
// Then print increasing order
cout << n << " ";
}
// Driver Program
int main()
{
int n = 16;
printPattern(n);
return 0;
}
Java 语言(一种计算机语言，尤用于创建网站)
// Java program to print pattern that first
// reduces 5 one by one, then adds 5.
// Without any loop an extra variable.
import java.io.*;
class GFG {
// Recursive function to print the
// pattern without any extra variable
static void printPattern(int n)
{
// Base case (When n becomes 0 or
// negative)
if (n == 0 || n < 0) {
System.out.print(n + " ");
return;
}
// First print decreasing order
System.out.print(n + " ");
printPattern(n - 5);
// Then print increasing order
System.out.print(n + " ");
}
// Driver Program
public static void main(String[] args)
{
int n = 16;
printPattern(n);
}
}
// This code is contributed by vt_m
Python 3
# Python3 program to print pattern that
# first reduces 5 one by one, then adds 5.
# Without any loop an extra variable.
# Recursive function to print the pattern
# without any extra variable
def printPattern(n):
# Base case (When n becomes 0 or negative)
if (n == 0 or n < 0):
print(n, end = ", ")
return
# First print decreasing order
print(n, end = ", ")
printPattern(n - 5)
# Then print increasing order
print(n, end = ", ")
# Driver Code
n = 16
printPattern(n)
# This code is contributed by
# Mohit kumar 29
C
// C# program to print pattern that first
// reduces 5 one by one, then adds 5.
// Without any loop an extra variable.
using System;
class GFG {
// Recursive function to print the
// pattern without any extra variable
static void printPattern(int n)
{
// Base case (When n becomes 0 or
// negative)
if (n == 0 || n < 0) {
Console.Write(n + " ");
return;
}
// First print decreasing order
Console.Write(n + " ");
printPattern(n - 5);
// Then print increasing order
Console.Write(n + " ");
}
// Driver Program
public static void Main()
{
int n = 16;
printPattern(n);
}
}
// This code is contributed by vt_m
服务器端编程语言（Professional Hypertext Preprocessor 的缩写）
<?php
// PHP program to print pattern
// that first reduces 5 one
// by one, then adds 5\. Without
// any loop an extra variable.
// Recursive function to print the
// pattern without any extra variable
function printPattern( $n)
{
// Base case (When n becomes
// 0 or negative)
if ($n == 0 or $n < 0)
{
echo $n , " ";
return;
}
// First print decreasing order
echo $n , " ";
printPattern($n-5);
// Then print increasing order
echo $n , " ";
}
// Driver Code
$n = 16;
printPattern($n);
// This code is contributed by anuj_67.
?>
java 描述语言
<script>
// Javascript program to print pattern that first reduces 5 one
// by one, then adds 5\. Without any loop an extra variable.
// Recursive function to print the pattern without any extra
// variable
function printPattern(n)
{
// Base case (When n becomes 0 or negative)
if (n == 0 || n < 0)
{
document.write(n + ", ");
return;
}
// First print decreasing order
document.write(n + ", ");
printPattern(n - 5);
// Then print increasing order
document.write(n + ", ");
}
let n = 16;
printPattern(n);
// This code is contributed by suresh07.
</script>
输出:
16, 11, 6, 1, -4, 1, 6, 11, 16
感谢 AKSHAY RATHORE 提出上述解决方案。 本文由高森供稿。如果发现有不正确的地方，请写评论，或者想分享更多关于以上讨论话题的信息
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