给定一个偶数N。任务是考虑从1到N 2的数字,将它们分成相等数目的N个组。
例子:
Input: N = 2
Output: {1, 4}, {2, 3}
Two groups of equal sum are 1, 4 and 2,3
Input: N = 4
Output:
{ 1, 16} { 2, 15}
{ 3, 14} { 4, 13}
{ 5, 12} { 6, 11}
{ 7, 10} { 8, 9}
方法:前N 2个数字之和的公式: Sum =(N 2 *(N 2 +1))/ 2 。
因此,每个组的总和将是=(N 2 + 1)* N 2/2
让我们考虑以下类型的对(1,N 2 ),(2,N 2 -1),依此类推。
由于N 2是偶数,所以可以使用正好N / 2个这样的对来构成每个组。
下面是上述方法的实现:
C++
// C++ implementation of the above approach
#include
using namespace std;
// Function to print N groups of equal sum
void printGroups(int n)
{
int x = 1;
int y = n * n;
// No. of Groups
for (int i = 1; i <= n; i++) {
// n/2 pairs
for (int j = 1; j <= n / 2; j++) {
cout << "{ " << x << ", " << y << "} ";
x++;
y--;
}
cout << endl;
}
}
// Driver code
int main()
{
int n = 4;
printGroups(n);
return 0;
}
Java
// Java implementation of the above approach
import java.io.*;
class GFG {
// Function to print N groups of equal sum
static void printGroups(int n)
{
int x = 1;
int y = n * n;
// No. of Groups
for (int i = 1; i <= n; i++) {
// n/2 pairs
for (int j = 1; j <= n / 2; j++) {
System.out.print("{ " + x + ", " + y + "} ");
x++;
y--;
}
System.out.println();
}
}
// Driver code
public static void main (String[] args) {
int n = 4;
printGroups(n);
}
}
// This code is contributed by shs
Python3
# Python implementation of the above approach
# Function to print N groups of equal sum
def printGroups(n) :
x = 1
y = n * n
# No. of Groups
for i in range(1, n + 1) :
# n/2 pairs
for j in range(1, n // 2 + 1) :
print("{",x,",",y,"}",end = " ")
x += 1
y -= 1
print()
# Driver code
if __name__ == "__main__" :
n = 4
# Function call
printGroups(n)
# This code is contributed by Ryuga
C#
// Java implementation of the
// above approach
using System;
class GFG
{
// Function to print N groups
// of equal sum
static void printGroups(int n)
{
int x = 1;
int y = n * n;
// No. of Groups
for (int i = 1; i <= n; i++)
{
// n/2 pairs
for (int j = 1; j <= n / 2; j++)
{
Console.Write("{ " + x + ", " + y + "} ");
x++;
y--;
}
Console.WriteLine();
}
}
// Driver code
public static void Main ()
{
int n = 4;
printGroups(n);
}
}
// This code is contributed by shs
PHP
输出:
{ 1, 16} { 2, 15}
{ 3, 14} { 4, 13}
{ 5, 12} { 6, 11}
{ 7, 10} { 8, 9}