沙漏图形 tri2str [1*+]

#include<bits/stdc++.h>
using namespace std;
#define ll long long
const double pi=acos(-1.0);
const double eps=1e-8;
const int maxn=100005;
int main()
{
    int n;
    scanf("%d",&n);
    for(int i=1; i<=n; i++)
    {
        for(int j=1; j<=2*n-1; j++)
        {
            if(j>=i&&j<=2*n-i)
            {
                if(i%2)
                {
                    if(j%2==0)
                    {
                        printf(" ");
                    }
                    else printf("*");
                }
                else
                {
                    if(j%2==0)
                    {
                        printf("*");
                    }
                    else printf(" ");
                }
            }
            else printf(" ");
        }
        printf("\n");
    }
    for(int i=1; i<=n-1; i++)
    {
        for(int j=1; j<=2*n-1; j++)
        {
            if(j>=n-i&&j<=n+i)
            {
                if(n%2)
                {
                    if(i%2)
                    {
                        if(j%2)
                        {
                            printf(" ");
                        }
                        else printf("*");
                    }
                    else
                    {
                        if(j%2) printf("*");
                        else printf(" ");
                    }
                }
                else
                {
                    if(i%2)
                    {
                        if(j%2)
                        {
                            printf("*");
                        }
                        else printf(" ");
                    }
                    else
                    {
                        if(j%2) printf(" ");
                        else printf("*");
                    }
                }

            }
            else printf(" ");
        }
        printf("\n");
    }


}