提解

简单

#include<bits/stdc++.h>
using namespace std;

int main(){
	int n;
    cin>>n;
    for(int i=1;i<=n;i++){
        for(int k=1;k<=n-i;k++){
            cout<<" ";
        }
        for(int j=1;j<=2*i-1;j++){
            if(j==1 || j==2*i-1){
                cout<<"*";
            }else{
                cout<<" ";
            }
        }
        cout<<endl;
    }
    
    for(int i=n-1;i>=1;i--){
        for(int k=1;k<=n-i;k++){
            cout<<" ";
        }
        for(int j=1;j<=2*i-1;j++){
            if(j==1 || j==2*i-1){
                cout<<"*";
            }else{
                cout<<" ";
            }
        }
        cout<<endl;
    }
	return 0;
}