题解 | #圣诞树#

#include <stdio.h>
int main() {
    int a, b;
    while (scanf("%d", &a) != EOF) {
        for (int i = 1; i <= a; i++) {
            for (int j = 1; j <= 3; j++) {
                for (int k = 1; k <= (a - i + 1) * 3 - j; k++) {
                    printf(" ");
                }
                b = 0;
                for (int m = 1; m <= j * i; m++) {
                    if (b == j) {
                        b = (6 - 2 * j);
                        if (b != 0) {
                            printf("%*c", b, ' ');
                        }
                        b = 0;
                    }
                    printf("* ");
                    b++;
                }
                printf("\n");
            }
        }
        for (int i = 0; i < a; i++) {
            for (int j = 0; j < a * 3 - 1; j++) {
                printf(" ");
            }
            printf("*\n");
        }
    }
    return 0;
}