Contest1261/F.cpp

#include<bits/stdc++.h>

using namespace std;

//问题 F神奇的数字 枚举优化(枚举一半)
const int T[] = {0,1, 10, 100, 1000, 10000, 100000, 1000000};

int main() {
    int n;
    cin >> n;
    char s[100];
    if (n & 1) {
        int a = n / 2 + 1;
        for (int i = T[a]; i < T[a + 1]; i++) {
            sprintf(s,"%d",i);
            cout<<s;
            s[strlen(s)-1]=0;
            reverse(s,s+strlen(s));
            cout<<s<<endl;
        }
    }else{
        int a = n / 2 ;
        for (int i = T[a]; i < T[a + 1]; i++) {
            sprintf(s,"%d",i);
            cout<<s;
            reverse(s,s+strlen(s));
            cout<<s<<endl;
        }
    }

    return 0;
}