#include <stdio.h>
#include <math.h>
main()
{
    int m,n=0,i,j,k;
   
    printf("Input N(3<N<20):");
    scanf("%D",&n);
   
    for(j=0;j<n;++j)printf("T");
    printf("\nTJ");
    for(j=0;j<n-4;++j)printf("J");
    printf("JT\n");
   
    m=(n-4)/2;
    for(i=-m;i<=m;++i)
    {
        printf("TJ");
        for(j=1;j<=m-abs(i);++j)printf("%d",j);
        if(i!=0)for(k=j*2;k<=(m)*2+m%2;++k)printf("%d",m-abs(i)+1);
        for(j=m-abs(i)+1;j>=1;--j)printf("%d",j);
        if(i==0&&n%2==0)for(k=0;k<n;++k)printf("\b");
        else
        printf("JT\n");
    }
   
    printf("TJ");
    for(j=0;j<n-4;++j)printf("J");
    printf("JT\n");
    }

就这几行吧
 for(i=-m;i<=m;++i)
    {
        printf("TJ");
        for(j=1;j<=m-abs(i);++j)printf("%d",j);
        if(i!=0)for(k=j*2;k<=(m)*2+m%2;++k)printf("%d",m-abs(i)+1);
        for(j=m-abs(i)+1;j>=1;--j)printf("%d",j);
        if(i==0&&n%2==0)for(k=0;k<n;++k)printf("\b");
        else
        printf("JT\n");
    }