#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
int main(){
    ios::sync_with_stdio(false);
    
    cout<<"----./--.../--..."<<endl;

    return 0;
}
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 */

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
int days[13]={0,31,28,31,30,31,30,31,31,30,31,30,31};

int cal(int x)
{
	int sum=0;
	while(x)
	{
		sum+=x%10;
		x/=10;
	}
	return sum;
}

int judge(int a,int b,int c)
{
	int sum=cal(a)+cal(b)+cal(c);
	return sum;
}

int main()
{
	int ans=0,countt=0;
	for(int year=2001;year<=2021;++year)
	{
		if((year%4==0&&year%100!=0)||year%400==0) days[2]=29;
		else days[2]=28;//不能漏了= =，初始化
		for(int month=1;month<=12;++month)
		{
			for(int day=1;day<=days[month];++day)
			{
				ans=judge(year,month,day);
				if(ans==1||ans==4||ans==9||ans==16||ans==25||ans==36||ans==49||ans==64) countt++;
			}
		}
	}
	cout<<countt<<"\n";
	return 0;
}

打卡

#include <bits/stdc++.h>
#define mod 1000000007
#define ll  unsigned long long
int month[13]={0,31,28,31,30,31,30,31,31,30,31,30,31};
using namespace std;
int solve(int x){
	int ans=0;
	while(x){
		ans+=x%10;
		x/=10;
	}
	return ans;
}
int main(){
	ll sum=0;
	for(int i=2001;i<=2021;i++){
		if((i%4==0&&i%100!=0)||i%400==0) month[2]=29;
		else month[2]=28;
		for(int k=1;k<=12;k++){
			for(int s=1;s<=month[k];s++){
				int ans=solve(i)+solve(k)+solve(s);
				if(sqrt(ans)==(int)sqrt(ans)){
					sum++;
				}
			}
		}
	}
	cout<<sum;
	return 0;
}

题目来源

2021年蓝桥杯国赛C题

题目链接：http://acm.mangata.ltd/p/P1504

考点

暴力枚举，常识or手数

视频讲解

视频连接：https://www.bilibili.com/video/BV15S4y1o78D/

思路

思路一

因为从2001年1月1日到2021年12月31日也就二十年，我们直接打开日历手动计数就好啦，肥肠的方便！

思路二

我们可以通过计算机辅助我们计算，我们开三重循环，分别模拟year、month、day，然后把每一天都拿来计算就好啦，然后要注意的是闰年的2月是29天，不过好在没有这一天是一个完全平方数。

代码

#include<bits/stdc++.h>
using namespace std;
//----------------自定义部分----------------
#define ll long long
#define mod 1000000009
#define endl "\n"
#define PII pair<int,int>

int dx[4]={0,-1,0,1},dy[4]={-1,0,1,0};

ll ksm(ll a,ll b) {
	ll ans = 1;
	for(;b;b>>=1LL) {
		if(b & 1) ans = ans * a % mod;
		a = a * a % mod;
	}
	return ans;
}

ll lowbit(ll x){return -x & x;}

const int N = 2e6+10;
//----------------自定义部分----------------

int month_day[13]={0,31,28,31,30,31,30,31,31,30,31,30,31};//每个月的天数

int f(int x){
	int ans = 0;
	while(x) {
		ans += x % 10;
		x /= 10;
	}
	return ans;
}

bool check(int a,int b,int c){
	int k = f(a) + f(b) + f(c);
	int p = sqrt(k);//默认向下取整的
	return p * p == k;
}

int main()
{
	
	int ans = 0;
	for(int year = 2001; year <= 2021; ++year){
		if((year % 4 == 0 && year % 100 != 0) || (year % 400 == 0)) month_day[2] = 29;
		else month_day[2] = 28;
		for(int month = 1;month <= 12; ++month){
			for(int day = 1;day <= month_day[month]; ++day){
				if(check(year,month,day)) ans++;
			}
		}
	}
	cout<<ans<<endl;
	
	return 0;
}