找到唯一的对,使每个元素小于或等于N

给定一个整数N,找到并显示满足以下条件的对数:

null
  • 这两个数字之间距离的平方等于 LCM 在这两个数字中。
  • 这个 GCD 这两个数的乘积等于两个连续整数的乘积。
  • 这对中的两个数字都应小于或等于N。

注: 仅应显示同时符合上述两种条件的配对,且这些数字必须小于或等于N。

例如:

Input: 10Output: No. of pairs = 1        Pair no. 1 --> (2, 4)Input: 500Output: No. of pairs = 7        Pair no. 1 --> (2, 4)        Pair no. 2 --> (12, 18)        Pair no. 3 --> (36, 48)        Pair no. 4 --> (80, 100)        Pair no. 5 --> (150, 180)        Pair no. 6 --> (252, 294)        Pair no. 7 --> (392, 448)

说明: 下表将清楚地显示将要查找的内容:

图片[1]-找到唯一的对,使每个元素小于或等于N-yiteyi-C++库

上表显示了两个连续数字及其对应倍数的乘积形成的GCD,其中每个值对应一对唯一。每行中的绿色条目构成对应GCD的唯一对。 注: 在上面的表格中,

  1. 对于第一个条目,GCD=2,2的第一个和第二个倍数构成唯一的一对(2,4)
  2. 同样,对于第二个条目,GCD=6,第二个和第三个6的倍数构成唯一的一对(12,18)
  3. 类似地,对于Zth条目,即对于GCD=Z*(Z+1),很明显,唯一对将由Zth和GCD=Z*(Z+1)的第(Z+1)个倍数组成。现在,GCD的Zth倍数是Z*(Z*(Z+1)),GCD的(Z+1)倍数将是(Z+1)*(Z*(Z+1))。
  4. 因为极限是N,所以唯一对中的第二个数必须小于或等于N。所以,(Z+1)*(Z*(Z+1))<=N。进一步简化它,得到所需的关系式Z 3. +(2*Z) 2. )+Z<=N

这形成了一种模式,通过数学计算,得出对于给定的N,这种唯一对的总数(比如Z)将遵循如下所示的数学关系:

Z3 + (2*Z2) + Z <= N

以下是所需的实施:

C

// C program for finding the required pairs
#include <stdio.h>
#include <stdlib.h>
// Finding the number of unique pairs
int No_Of_Pairs( int N)
{
int i = 1;
// Using the derived formula
while ((i * i * i) + (2 * i * i) + i <= N)
i++;
return (i - 1);
}
// Printing the unique pairs
void print_pairs( int pairs)
{
int i = 1, mul;
for (i = 1; i <= pairs; i++) {
mul = i * (i + 1);
printf ( "Pair no. %d --> (%d, %d)" ,
i, (mul * i), mul * (i + 1));
}
}
// Driver program to test above functions
int main()
{
int N = 500, pairs, mul, i = 1;
pairs = No_Of_Pairs(N);
printf ( "No. of pairs = %d " , pairs);
print_pairs(pairs);
return 0;
}


JAVA

// Java program for finding
// the required pairs
import java.io.*;
class GFG
{
// Finding the number
// of unique pairs
static int No_Of_Pairs( int N)
{
int i = 1 ;
// Using the derived formula
while ((i * i * i) +
( 2 * i * i) + i <= N)
i++;
return (i - 1 );
}
// Printing the unique pairs
static void print_pairs( int pairs)
{
int i = 1 , mul;
for (i = 1 ; i <= pairs; i++)
{
mul = i * (i + 1 );
System.out.println( "Pair no. " + i + " --> (" +
(mul * i) + ", " +
mul * (i + 1 ) + ")" );
}
}
// Driver code
public static void main (String[] args)
{
int N = 500 , pairs, mul, i = 1 ;
pairs = No_Of_Pairs(N);
System.out.println( "No. of pairs = " + pairs);
print_pairs(pairs);
}
}
// This code is contributed by Mahadev.


Python3

# Python3 program for finding the required pairs
# Finding the number of unique pairs
def No_Of_Pairs(N):
i = 1 ;
# Using the derived formula
while ((i * i * i) + ( 2 * i * i) + i < = N):
i + = 1 ;
return (i - 1 );
# Printing the unique pairs
def print_pairs(pairs):
i = 1 ;
mul = 0 ;
for i in range ( 1 , pairs + 1 ):
mul = i * (i + 1 );
print ( "Pair no." , i, " --> (" , (mul * i),
", " , mul * (i + 1 ), ")" );
# Driver Code
N = 500 ;
i = 1 ;
pairs = No_Of_Pairs(N);
print ( "No. of pairs = " , pairs);
print_pairs(pairs);
# This code is contributed
# by mits


C#

// C# program for finding
// the required pairs
using System;
class GFG
{
// Finding the number
// of unique pairs
static int No_Of_Pairs( int N)
{
int i = 1;
// Using the derived formula
while ((i * i * i) +
(2 * i * i) + i <= N)
i++;
return (i - 1);
}
// Printing the unique pairs
static void print_pairs( int pairs)
{
int i = 1, mul;
for (i = 1; i <= pairs; i++)
{
mul = i * (i + 1);
Console.WriteLine( "Pair no. " + i + " --> (" +
(mul * i) + ", " +
mul * (i + 1) + ")" );
}
}
// Driver code
static void Main()
{
int N = 500, pairs;
pairs = No_Of_Pairs(N);
Console.WriteLine( "No. of pairs = " +
pairs);
print_pairs(pairs);
}
}
// This code is contributed by mits


PHP

<?php
// PHP program for finding
// the required pairs
// Finding the number
// of unique pairs
function No_Of_Pairs( $N )
{
$i = 1;
// Using the
// derived formula
while (( $i * $i * $i ) +
(2 * $i * $i ) +
$i <= $N )
$i ++;
return ( $i - 1);
}
// Printing the unique pairs
function print_pairs( $pairs )
{
$i = 1; $mul ;
for ( $i = 1;
$i <= $pairs ; $i ++)
{
$mul = $i * ( $i + 1);
echo "Pair no." ,
$i , " --> (" ,
( $mul * $i ), ", " ,
$mul * ( $i + 1), ") " ;
}
}
// Driver Code
$N = 500; $pairs ;
$mul ; $i = 1;
$pairs = No_Of_Pairs( $N );
echo "No. of pairs = " ,
$pairs , " " ;
print_pairs( $pairs );
// This code is contributed
// by Akanksha Rai(Abby_akku)
?>


Javascript

<script>
// Javascript program for finding the
// required pairs
// Finding the number of unique pairs
function No_Of_Pairs(N)
{
let i = 1;
// Using the derived formula
while ((i * i * i) +
(2 * i * i) + i <= N)
i++;
return (i - 1);
}
// Printing the unique pairs
function print_pairs(pairs)
{
let i = 1, mul;
for (i = 1; i <= pairs; i++)
{
mul = i * (i + 1);
document.write( "Pair no. " + i +
" --> (" + (mul * i) +
", " + mul * (i + 1) +
")<br>" );
}
}
// Driver code
let N = 500, pairs, mul, i = 1;
pairs = No_Of_Pairs(N);
document.write( "No. of pairs = " +
pairs + "<br>" );
print_pairs(pairs);
// This code is contributed by mohit kumar 29
</script>


输出:

No. of pairs = 7 Pair no. 1 --> (2, 4)Pair no. 2 --> (12, 18)Pair no. 3 --> (36, 48)Pair no. 4 --> (80, 100)Pair no. 5 --> (150, 180)Pair no. 6 --> (252, 294)Pair no. 7 --> (392, 448)

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