#include <stdio.h>

int main()
{
 FILE *in = fopen("input.txt", "r");
 FILE *out = fopen("output.txt", "w");
 
    int cnt;
 int i,j;

 fscanf(in, "%d", &cnt);

 for(i=1; i<=cnt; i++){
  for(j=1; j<=cnt-i; j++){
   fprintf(out, "  ");
  }
  for(j=1; j<=i*2-1; j++){
   fprintf(out, "* ");
  }
  fprintf(out, "\n");
 }

 for(i=cnt-1; i>=1; i--){
  for(j=cnt-i; j>=1; j--){
   fprintf(out, "  ");
  }
  for(j=i*2-1; j>=1; j--){
   fprintf(out, "* ");
  }
  fprintf(out, "\n");
 }

 return 0;
}

결과가 맞게 나오는걸 확인했는데 제출하면 오답이라고 나오네요..