Codeforces Beta Round #44 (Div. 2)

Codeforces Beta Round #44 (Div. 2)

http://codeforces.com/contest/47

A

 #include<bits/stdc++.h>
 using namespace std;
 #define lson l,mid,rt<<1
 #define rson mid+1,r,rt<<1|1
 #define sqr(x) ((x)*(x))
 #define pb push_back
 #define maxn 1000005
 typedef long long ll;
 typedef unsigned long long ull;

 int main(){
     #ifndef ONLINE_JUDGE
       //  freopen("input.txt","r",stdin);
     #endif
     std::ios::sync_with_stdio(false);
     map<int,int>mp;
     for(int i=;i<=;i++){
         mp[i*(i+)/]=;
     }
     int n;
     cin>>n;
     if(mp[n]) cout<<"YES"<<endl;
     else cout<<"NO"<<endl;

 }

B

 #include<bits/stdc++.h>
 using namespace std;
 #define lson l,mid,rt<<1
 #define rson mid+1,r,rt<<1|1
 #define sqr(x) ((x)*(x))
 #define pb push_back
 #define maxn 1000005
 typedef long long ll;
 typedef unsigned long long ull;

 struct sair{
     char ch;
     int v;
     bool operator<(const sair &b)const{
         return v>b.v;
     }
 }s;

 int main(){
     #ifndef ONLINE_JUDGE
         freopen("input.txt","r",stdin);
     #endif
     std::ios::sync_with_stdio(false);
     int a,b,c;
     string str;
     map<char,int>mp;
     mp['A']++;
     mp['B']++;
     mp['C']++;
     for(int i=;i<=;i++){
         cin>>str;
         if(str[]=='>'){
             mp[str[]]++;
         }
         else{
             mp[str[]]++;
         }
     }
     vector<sair>ve;
     int book[];
     memset(book,,sizeof(book));
     for(map<char,int>::iterator it=mp.begin();it!=mp.end();it++){
         s.ch=it->first;
         s.v=it->second;
         if(book[s.v]){
             cout<<"Impossible"<<endl;
             return ;
         }
         book[s.v]=;
         ve.push_back(s);
     }
     sort(ve.begin(),ve.end());
     for(int i=;i<ve.size();i++){
         cout<<ve[i].ch;
     }

 }

C

大模拟

 #include<bits/stdc++.h>
 using namespace std;
 #define lson l,mid,rt<<1
 #define rson mid+1,r,rt<<1|1
 #define sqr(x) ((x)*(x))
 #define pb push_back
 #define maxn 1000005
 typedef long long ll;
 typedef unsigned long long ull;

 vector<string>ans;
 string s[];
 bool add(char &a,char b){if (a!='.'&&a!=b)return ;a=b;return ;}

 int main(){
     #ifndef ONLINE_JUDGE
         freopen("input.txt","r",stdin);
     #endif
     std::ios::sync_with_stdio(false);
     for (int i=;i<=;i++)cin>>s[i];
     sort(s,s+);
     do{
         vector<string>v(s[].size(),string(s[].size(),'.'));
         if (s[].size()!=s[].size()+s[].size()-) continue;
         if (s[].size()!=s[].size()+s[].size()-) continue;
         bool fl=;
         for (int i=;i<s[].size();i++)fl&=add(v[i][s[].size()-],s[][i]);
         for (int i=;i<s[].size();i++)fl&=add(v[s[].size()-][i],s[][i]);
         for (int i=;i<s[].size();i++)fl&=add(v[][i],s[][i]);
         for (int i=;i<s[].size();i++)fl&=add(v[i][],s[][i]);
         for (int i=;i<s[].size();i++)fl&=add(v[s[].size()-+i][s[].size()-],s[][i]);
         for (int i=;i<s[].size();i++)fl&=add(v[s[].size()-][s[].size()-+i],s[][i]);
         if (!fl)    continue;
         if (ans.empty()||v<ans)    ans=v;
     }while (next_permutation(s,s+));
     if (ans.empty())    cout<<"Impossible"<<endl;
         else for(auto i:ans) cout<<i<<endl;
 }

D

暴力搜索

 #include<bits/stdc++.h>
 using namespace std;
 #define lson l,mid,rt<<1
 #define rson mid+1,r,rt<<1|1
 #define sqr(x) ((x)*(x))
 #define pb push_back
 #define maxn 1000005
 typedef long long ll;
 typedef unsigned long long ull;

 char s[][];
 int c[],n,m,ans;
 void dfs(int t)
 {
     int i,j;
     for(i=;i<m;i++)
         if(c[i]<)return ;
     if(t>=n)
     {
         for(i=;i<m;i++)
             if(c[i]>) return ;
         ans++;
         return ;
     }
     for(i=;i<=;i++)
     {
         for(j=;j<m;j++)
             if(s[j][t]==(i+''))c[j]--;
         dfs(t+);
         for(j=;j<m;j++)
             if(s[j][t]==(i+''))c[j]++;
     }
 }

 int main(){
     #ifndef ONLINE_JUDGE
         freopen("input.txt","r",stdin);
     #endif
     std::ios::sync_with_stdio(false);
     cin>>n>>m;
     for(int i=;i<m;i++)cin>>s[i]>>c[i];
     ans=;
     dfs();
     cout<<ans<<endl;
 }

E

几何，把子弹按角度从小到大排序，然后模拟

 #include<bits/stdc++.h>
 using namespace std;
 #define lson l,mid,rt<<1
 #define rson mid+1,r,rt<<1|1
 #define sqr(x) ((x)*(x))
 #define pb push_back
 #define maxn 1000005
 typedef long long ll;
 typedef unsigned long long ull;

 const double g=9.8;
 double v,al[],ss[],cc[];
 int d[];
 pair<double,double> w[];
 double x[];

 double run(double x,double alpha)
 {
     return (v*sin(alpha)+v*sin(alpha)-g*x/(v*cos(alpha)))*x/(v*cos(alpha))/;
 }
 bool cmp(const int &a,const int &b)
 {
     return al[a]<al[b];
 }

 int main(){
     #ifndef ONLINE_JUDGE
         freopen("input.txt","r",stdin);
     #endif
     std::ios::sync_with_stdio(false);
     int n,m;
     scanf("%d%lf",&n,&v);
     for(int i=;i<=n;i++)
         scanf("%lf",&al[d[i]=i]),cc[i]=cos(al[i]),ss[i]=sin(al[i]);
     sort(d+,d++n,cmp);
     scanf("%d",&m);
     for(int i=;i<=m;i++)
         scanf("%lf%lf",&w[i].first,&w[i].second);
     sort(w+,w++m);
     int j=;
     for(int i=;i<=n;i++)
     {
         while(j<=m&&run(w[j].first,al[d[i]])>w[j].second)j++;
         if(j>m||run(w[j].first,al[d[i]])<)
         {
             x[d[i]]=v*ss[d[i]]/g**v*cc[d[i]];
             continue;
         }
         x[d[i]]=w[j].first;
     }
     for(int i=;i<=n;i++)
         printf("%.9lf %.9lf\n",x[i],run(x[i],al[i]));
 }