Codeforces Round #617 (Div. 3) A~D

链接

#include<bits/stdc++.h>

using namespace std;
typedef long long ll;

const int N = 1e5+10;

int a[N] = {0};

int main(int argc, char const *argv[])
{
	int T;
	ios::sync_with_stdio(false);
	cin>>T;
	while(T--)
	{
		int n,k;
		cin>>n;
		int num=0;
		int flag = 0;
		int temp = 0;
		for (int i = 0; i < n; ++i)
		{
			cin>>a[i];
			if (a[i]&1)
			{
				num++;
			}
			if (i==0)
			{
				temp=a[i];
			}

		}
		if (num<n&&num>=1||num==n&&n&1)
		{
				cout<<"YES"<<endl;
		}
		else
				cout<<"NO"<<endl;
	}
	return 0;
}

链接

每次不花个位数上的钱就可以

#include<bits/stdc++.h>

using namespace std;
typedef long long ll;



int main(int argc, char const *argv[])
{
	int T;
	ios::sync_with_stdio(false);
	cin>>T;
	while(T--)
	{
		int n;
		cin>>n;
		ll ans = 0;
		int temp = n;
		int k = 1;
		int t = 1;
		while(n>=10)
		{
			ans += (n/10)*10; //花更多
			n = n-(n/10)*10+n/10;

		}
		ans += n;
		cout<<ans<<endl;
	}
	return 0;
}

链接

消除一段而不影响终点，相当于删除的这一段走的其实是一个圈
建立map映射点和这段序列的下标即可

#include<bits/stdc++.h>

using namespace std;

const int N = 2e5+10;

char a[N];

map<pair<int,int>,int> mp;
 

int main(int argc, char const *argv[])
{
	int T;
	cin>>T;
	while(T--)
	{
		int n = 0;
		cin>>n;
		cin>>a;
		int ansl=0,ansr=0;
		int t=0,m=1e9+10;
		mp.clear();
		pair<int,int> temp;
		//mp[temp]=1;
		for (int i = 0; i < n; ++i)
		{
			if (a[i]=='L')
			{
				temp.first -= 1;
			}
			if (a[i]=='R')
			{
				temp.first = temp.first+1;
			}
			if (a[i]=='U')
			{
				temp.second = temp.second+1;
			}
			if (a[i]=='D')
			{
				temp.second =temp.second- 1;
			}
			//cout<<temp.first<<" "<<temp.second<<endl;
			if (mp[temp]>0&&i+1-mp[temp]<m||temp==make_pair(0,0)&&i+1-mp[temp]<m)
			{
				ansl = mp[temp]+1;
				ansr = i+1;
				m = i+1-mp[temp];
			}
			mp[temp]=i+1;

		}
		if (m<1e9+10)
		{
			cout<<ansl<<" "<<ansr<<endl;
		}
		else
			cout<<"-1"<<endl;
	}
	return 0;
}

链接

预处理所有妖怪的生命值，算出所需要的跳过的次数，排序后遍历即可

#include<bits/stdc++.h>

using namespace std;
typedef long long ll;

const int N = 2e5+10;

int hp[N] = {0};
vector<int > v;
int main(int argc, char const *argv[])
{
	
	ios::sync_with_stdio(false);
	int n,a,b,k;
	ll ans = 0;
	cin>>n>>a>>b>>k;
	for (int i = 0; i < n; ++i)
	{
		cin>>hp[i];
	}
	for (int i = 0; i < n; ++i)
	{
		if (hp[i]%(a+b)>0&&hp[i]%(a+b)<=a)
		{
			ans++;
		}
		else if(hp[i]%(a+b)==0)
		{
			int gap = b;
			if (gap%a==0)
			{
				v.push_back(gap/a);
			}
			else 
				v.push_back(b/a+1);

		}
		else 
		{
			int temp = (hp[i]%(a+b)-a);
			if (temp%a==0)
			{
				v.push_back(temp/a);
			}
			else
				v.push_back(temp/a+1);
		}
	}
	sort(v.begin(),v.end());
	for (int i = 0; i < v.size(); ++i)
	{
		k-=v[i];
		if (k>=0)
		{
			ans++;
		}
		else
			break;
	}
	cout<<ans<<endl;
	return 0;

}