第十四届蓝桥杯集训——练习解题阶段(无序阶段)-ALGO-2 算法训练 最大最小公倍数

#include <stdio.h>
#include <stdlib.h>
#define MAXSIZE 10000

//输出值
void Print(char *num,int n)
{
	int i;
	for(i=n-1;i>=0;i--)
	{
		printf("%c",num[i]);
	}
	printf("\0");
	printf("\n");
}

//对字符数组进行初始化
void Init(char *num)
{
	int i;
	for(i=0;i<MAXSIZE;i++) num[i]='0';
}

//将一个整数转换为字符类型
int TransformString(char *num,int value)
{
	int num_n=0;
	while(value)
	{
		num[num_n++]=value%10+'0';
		value/=10;
	}
	return num_n;
}

//两个大整数相乘
int Multiplication(char *num1,int num1_n,char *num2,int num2_n,char *result,int result_n)
{
	int i,j;
	int carry;
	int value;
	for(i=0;i<num2_n;i++)
	{
		carry=0;
		for(j=0;j<num1_n;j++)
		{
			value=(num2[i]-'0')*(num1[j]-'0')+(result[i+j]-'0')+carry;
			carry=value/10;
			result[i+j]=value%10+'0';
		}
		if(carry)
		{
			result[i+j]=carry+'0';
			result_n=i+j+1;
		}
		else result_n=i+j;
	}
	return result_n;
}

//判断两个数是否有公约数
int GCD(int num1,int num2)
{
	int temp;
	while(num2)
	{
		temp=num1%num2;
		num1=num2;
		num2=temp;
	}
	if(num1==1) return 1;
	else return 0;
}

//选出满足条件的值
void Select(int n)
{
	char num1[MAXSIZE];
	char num2[MAXSIZE];
	char result[MAXSIZE];
	int num1_n;
	int num2_n;
	int result_n=0;
	int n1;
	int n2;
	int n3;

	if(n%2==1)
	{
		n1=n;
		n2=n-1;
		n3=n-2;
	}
	else
	{
		n1=n;
		n2=n-1;
		n3=n-3;

		while( GCD(n1,n3)!=1 || GCD(n2,n3)!=1) n3--;
		if(n3!=n-3)
		{
			n1=n-1;
			n2=n-2;
			n3=n-3;
		}
	}
	num1_n=TransformString(num1,n1);
	num2_n=TransformString(num2,n2);
	Init(result);
	result_n=Multiplication(num1,num1_n,num2,num2_n,result,result_n);
	num1_n=TransformString(num1,n3);
	Init(num2);
	num2_n=0;
	num2_n=Multiplication(num1,num1_n,result,result_n,num2,num2_n);
	Print(num2,num2_n);
}

int main()
{
	int n;
	scanf("%d",&n);
	Select(n);
	return 0;
}

#include<iostream>
using namespace std;


//两个数的最大公约数
long long gcd(long long a,long long b)
{
    return b?gcd(b,a%b):a;
}

int main()
{
	long long n,a,b,r;
	while(cin>>n)
	{
		if(n%2==1)
			cout<<n*(n-1)*(n-2)<<endl;
		else
		{
			long long s1=(n-1)*(n-2)*(n-3);
			
			a=n*(n-1);
			while(gcd(n-2,a)!=1)n--;
			if((n-2)*a>s1)
				cout<<(n-2)*a<<endl;
			else
				cout<<s1<<endl;
		}
	}
	return 0;
} 

import java.math.BigInteger;
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String num = sc.next();
		sc.close();
		BigInteger n = new BigInteger(num);
		System.out.println(f(n));
	}

	public static BigInteger f(BigInteger n) {
		if (n.subtract(new BigInteger("3")).intValue() <= 0)
			return n.multiply(new BigInteger("2"));
		else if (n.mod(new BigInteger("2")).intValue() == 1) {
			return n.multiply(n.subtract(new BigInteger("1")).multiply(n.subtract(new BigInteger("2"))));
		} else {
			if (n.mod(new BigInteger("3")).intValue() == 0) {
				return n.subtract(new BigInteger("1"))
						.multiply(n.subtract(new BigInteger("2")).multiply(n.subtract(new BigInteger("3"))));
			} else {
				return n.multiply(n.subtract(new BigInteger("1")).multiply(n.subtract(new BigInteger("3"))));
			}
		}

	}
}

n=int(input())
if n%2:
    print(n*(n-1)*(n-2))
else:
    if n%3:
       print(n*(n-1)*(n-3)) 
    else:
        print((n-1)*(n-2)*(n-3))