Codeforces Round #590 (Div. 3)（e、f待补

https://codeforces.com/contest/1234/problem/A

A. Equalize Prices Again

 1 #include<bits/stdc++.h>
 2 using namespace std;
 3 typedef long long ll;
 4 int main(){
 5     int n,a;
 6     int t;
 7     cin>>t;
 8     ll sum = 0,ans;
 9     while(t--){
10         cin>>n;sum = 0;
11         for(int i = 0;i < n;++i){
12             cin>>a;sum+=a;
13         }
14         ans = sum/n;
15         if(sum%n)ans+=1;
16         cout<<ans<<endl;
17     }
18 }

AC代码

https://codeforces.com/contest/1234/problem/B1

B1. Social Network (easy version)

https://codeforces.com/contest/1234/problem/B2

B2. Social Network (hard version)

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
ll a;
int n ,k ,now=0,fi=0;
vector<ll>s;
map<ll,int>mp;
int main(){
    cin>>n>>k;
    for(int i = 0;i < n;++i){
        cin>>a;
        if(mp[a]==0){
                mp[a]=1;s.push_back(a);
            if(now<k){
                now++;
            }
            else if(now==k){
                mp[s[fi]]=0;fi++;
            }
        }
    }
    cout<<now<<endl;
    int l =s.size()-1;
    int cnt=0;
    while(cnt<now&&l>=0){
        if(mp[s[l]])cnt++,cout<<s[l]<<" ";
        l--;
    }
    cout<<endl;

    return 0;
}

AC代码

https://codeforces.com/contest/1234/problem/C

C. Pipes

旋转一遍发现前两种其实是不同方向摆放的一种管道，后四个同理，也就是只有两个管道，一个是直流另一个会变向，然后问题就很简单了。

 1 #include<bits/stdc++.h>
 2 using namespace std;
 3 typedef long long ll;
 4
 5 int main(){
 6     int t,n;
 7     cin>>t;
 8     while(t--){
 9         cin>>n;
10         string a[3];cin>>a[0]>>a[1];
11         int now=0,flag =1;
12         for(int i = 0;i <n;++i){
13             if(a[now][i]=='1'||a[now][i]=='2')continue;
14             else{
15                now=1-now;
16                if(a[now][i]=='1'||a[now][i]=='2'){
17                 flag=0;break;
18                }
19             }
20         }
21         if(flag==0||now==0)cout<<"no"<<endl;
22         else cout<<"yes"<<endl;
23     }
24     return 0;
25 }

AC代码

https://codeforces.com/contest/1234/problem/D

D. Distinct Characters Queries

用线段树维护不同字母的个数orz学到了新东西，待会再看看set的做法？