Link:
Codeforces https://codeforces.com/contest/1428

A. Box is Pull

讀錯題目 × 1

#include<cstdio>
#include<iostream>
#include<algorithm>
#include<cmath>
#include<cstring>
#include<cstdlib>
using namespace std;
int t;
int main()
{
	ios::sync_with_stdio(false);
	cin >> t;
		int aa, bb, cc, dd;
	while(t--)
	{
		cin >> aa >> bb >> cc >> dd;
		if(aa==cc)
		{
			cout<<abs(dd-bb)<<endl;continue;
		}
		if(bb==dd)
		{
			cout<<abs(aa-cc)<<endl;continue;
		}
		cout<<abs(dd-bb)+abs(cc-aa)+2<<endl;
		continue;
	}
	return 0;
}
 

B. Belted Rooms

沒反應過來題意就直接打了，浪費半小時
還 WA 了五發

#include<cstdio>
#include<iostream>
#include<algorithm>
#include<cmath>
#include<cstring>
#include<cstdlib>
using namespace std;
const int MAXN = 3e5 + 10;
int t, n, ans;
		char ch;
		bool headee;
		bool nota, notb;
		char chzer;
int main()
{
	cin >> t;
	while(t--)
	{
		cin >> n;
		headee = 0;
		ans = 0;
		nota = notb = false;
		chzer = '0';
		for (int i = 0; i<n; ++i)
		{
			cin>>ch;
			if(!i)chzer=ch;
			if(ch=='-')
			{
				if(!headee)++ans;
				headee=1;
				++ans;
			}
			else headee=0;
			if (ch=='>') nota=true;
			if(ch=='<')notb=true;
		}
		if (ch == chzer&&ch == '-') --ans;
		if(!nota||!notb)cout<<n<<endl;
		else cout<<ans<<endl;
		
	}
	return 0;
}
 

C. ABBB

怎麼說呢，意外地很好寫
注意到 B 只要前面有字母都可以去掉，很好貪心

#include<cstdio>
#include<iostream>
#include<algorithm>
#include<cmath>
#include<cstring>
#include<cstdlib>
using namespace std;
int t, n, ans;
char ch;
string s;
int main()
{
	cin >> t;
	while(t--)
	{
		cin >> s;
		n = s.length();
		ans = 0;
		for(int Ben=0, Aen=0, i=0; i<n; ++i)
		{
			ch = s[i];
			if(ch=='A')
			{
				++Aen;
			}
			if(ch=='B')
			{
				if(Aen)
				{
					--Aen;
					++ans;
				}
				else
				{
					if(Ben && !Aen)
					{
						--Ben;
						++ans;
					}
					else ++Ben;
				}
			}
		}
		cout<<n-(ans<<1)<<endl;
	}
	return 0;
}
 

D. Bouncing Boomerangs

睡了
反彈不會超過三次，所以很容易根據從哪裡進哪裡出約束一波