Codeforces round 580 (Div. 2) c- almost equal [Law]

Codeforces Round #580 (Div. 2) C- Almost Equal【 law 】

subject ：

http://codeforces.com/contest/1206/problem/C

General meaning ：

Input n, Put the numbers 1~2n In a circle , Make any two “ continuity n Sum of numbers ” The difference between them is no more than 1.

Ideas ：

Guess what n = even numbers There is no solution at all , Direct output NO.
n = Odd number When ,1 and 2 The location of this is certain ,1 Back up n-1 A digital , The first even numbers Yes The previous number +3, The first Odd number Yes The previous number +1.2 Back up n-1 A digital , The first even numbers Yes The previous number +1, The first Odd number Yes The previous number +3.

Code ：

#include<iostream>
#include<string.h>
#include<algorithm>
#include<cstdio>
#include<cstdlib>
using namespace std;
 
int main() {
    
	int n;
	scanf("%d",&n);
	if(n % 2 == 0) {
    
		printf("NO\n");
	}
	else {
    
		printf("YES\n");
		printf("1");
		int num = 1;
		for(int i = 0; i < n-1; i++) {
    
			if(i % 2 == 0) {
    
				printf(" %d",num+3);
				num += 3;
			}
			else {
    
				printf(" %d",num+1);
				num += 1;
			}
		}
		printf(" 2");
		num = 2;
		for(int i = 0; i < n-1; i++) {
    
			if(i % 2 == 0) {
    
				printf(" %d",num+1);
				num += 1;
			}
			else {
    
				printf(" %d",num+3);
				num += 3;
			}
		}
		printf("\n");
	}
	return 0;
}