A Easy Sort Problem

$$O(N)$$

#include <iostream>
#include <algorithm>
using namespace std;
struct Node {
    int num;
    int s; // 存个位数
};
bool cmp(const Node &x, const Node &y) {
    if(x.s != y.s) return x.s > y.s; 
    else return x.num < y.num;       
}
int main() {
    int n;
    cin >> n;
    Node a[100005];
    for(int i = 0; i < n; i++) {
        cin >> a[i].num;
        a[i].s = a[i].num % 10;
    }
    sort(a, a + n, cmp);
    for(int i = 0; i < n; i++) {
        cout << a[i].num << "\n";
    }
    return 0;
}