题解 | #[NOIP2016]回文日期#

```#include <iostream>
#include <algorithm>
#include <vector>
bool isLeap(int y) {
    return (y % 4 == 0 && y % 100 != 0) || (y % 400 == 0);
}

using namespace std;
int main(){
	ios::sync_with_stdio(false);
	cin.tie(nullptr),cout.tie(nullptr);
	string op , ed;      cin >> op >> ed;
	string op_year , op_month , op_day , ed_year , ed_month , ed_day;
	op_year = op.substr(0 , 4); op_month = op.substr(4,2);   op_day = op.substr(6,2);
	ed_year = ed.substr(0 , 4); ed_month = ed.substr(4,2);   ed_day = ed.substr(6,2);
	int b_y = stoi(op_year) , b_m = stoi(op_month) , b_d = stoi(op_day);
	int e_y = stoi(ed_year) , e_m = stoi(ed_month) , e_d = stoi(ed_day);
	int cur_y = b_y;
	int res = 0 ; 
	while(cur_y <= e_y ){
		string cur = to_string(cur_y);
		string R_cur = cur;
		reverse(R_cur.begin() , R_cur.end());
		string R_m = R_cur.substr(0,2);
		string R_d = R_cur.substr(2,2);
		int R_month = stoi(R_m);
		int R_day = stoi(R_d);
		if(R_month > 12 ||(R_month == 2 && R_day > 29 && isLeap(cur_y)) || (R_month == 2 && R_day > 28 && !isLeap(cur_y)) ||
		  ((R_month == 1 || R_month == 3 || R_month == 5 || R_month == 7 || R_month == 8 || R_month == 10 || R_month == 12) && R_day > 31) ||
		  ((R_month == 4 || R_month == 6 || R_month == 9 || R_month == 11) && R_day > 30)||
		  (R_month == 0) || (R_day == 0)
		){
			cur_y ++;
			continue ; 
		}
		res ++;
		cur_y ++;
	}
	cout << res << endl;
	return 0;
}

我的臭虫代码喵呜呜，hia ~TT ,我的想法把遍历年份翻转检验月和日的合法性，存在的话res++