哈哈哈，沙发～～～

代码奉上！

#include <iostream>
using namespace std;

void printC(int n,char c) {
    while(n--) cout << c;
}

int main() {
    int n;
    char c;
    cin >> n >> c;
    for(int i = 0;i < n - 1;i++) {
        int space = n - i - 1;
        int pchar = i * 2 + 1;
        printC(space,' ');
        printC(pchar,c);
        printC(1,'\n');
    }
    printC(n * 2 - 1,c);
    printC(1,'\n');
    for(int i = 0;i < n - 2;i++) {
        int space = i + 1;
        int pchar = (n - i - 2) * 2 + 1;
        printC(space,' ');
        printC(pchar,c);
        printC(1,'\n');
    }
    int space = n - 1;
    int pchar = 1;
    printC(space,' ');
    printC(pchar,c);
    return 0;
}

无任何防抄袭措施
可自行复制食用

“hello world!"