难度还行

#include <bits/stdc++.h>

using namespace std;

int main() {
int n, a = 1, c = 1;
char b = ' ', d = '*';
scanf("%d", &n);
int e = n;
do {
for (int i = 1; i < e; ++i) {
printf("%c", b);
}
for (int j = 1; j <= a; ++j) {
printf("%c", d);
}
printf("\n");
a += 2;
++c;
--e;
} while (c <= n);
return 0;
}