Codeforces Beta Round #67 (Div. 2)

Codeforces Beta Round #67 (Div. 2)

http://codeforces.com/contest/75

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 eb emplace_back
 #define maxn 1000006
 #define eps 1e-8
 #define pi acos(-1.0)
 #define rep(k,i,j) for(int k=i;k<j;k++)
 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);
     int a,b,c;
     cin>>a>>b;
     c=a+b;
     int ccc=;
     int aa=,bb=,cc;
     int p=;
     while(a){
         int tmp=a%;
         if(tmp!=){
            aa+=(tmp)*p;
            p*=;
         }
         a/=;
     }
     p=;
     while(b){
         int tmp=b%;
         if(tmp!=){
            bb+=(tmp)*p;
            p*=;
         }
         b/=;
     }
     p=;
     while(c){
         int tmp=c%;
         if(tmp!=){
            ccc+=(tmp)*p;
            p*=;
         }
         c/=;
     }
     cc=aa+bb;
     if(cc==ccc) cout<<"YES"<<endl;
     else cout<<"NO"<<endl;
 }

B

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 eb emplace_back
 #define maxn 1000006
 #define eps 1e-8
 #define pi acos(-1.0)
 #define rep(k,i,j) for(int k=i;k<j;k++)
 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);
     string me;
     cin>>me;
       int n;
     cin>>n;
       map<string,int>M,S{{"posted",},{"commented",},{"likes",}};
       for(string a,b,c,x;cin>>a>>b>>c>>x;M[a],M[c])
     {
         if(c=="on")c=x,cin>>x;
         c.pop_back();c.pop_back();
         if(a==me)M[c]+=S[b];
         if(c==me)M[a]+=S[b];
       }
       vector<pair<int,string>>V;
       for(map<string,int>::iterator it=M.begin();it!=M.end();it++)V.emplace_back(-it->second,it->first);
       sort(V.begin(),V.end());
       for(int i=;i<V.size();i++)if(V[i].second!=me)cout<<V[i].second<<endl;
 }

C

二分+gcd

 #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 eb emplace_back
 #define maxn 1000006
 #define eps 1e-8
 #define pi acos(-1.0)
 #define rep(k,i,j) for(int k=i;k<j;k++)
 typedef long long ll;
 typedef unsigned long long ull;

 int aa,bb,l,r,x,y;
 int a[];

 int main(){
     #ifndef ONLINE_JUDGE
      //   freopen("input.txt","r",stdin);
     #endif
     std::ios::sync_with_stdio(false);
     cin>>aa>>bb;
     int n;
     cin>>n;
     int gcd=__gcd(aa,bb);
     int co=;
     int gg=sqrt(gcd);
     a[co++]=;
     for(int i=;i<=gg;i++){
         if(gcd%i==){
             a[co++]=i;
             if(gcd/i!=gg){
                 a[co++]=gcd/i;
             }
         }
     }
     a[co++]=gcd;
     sort(a+,a+co);
     int mid;
     for(int i=;i<=n;i++){
         cin>>x>>y;
         l=,r=co-;
         while(l<=r){
             mid=l+r>>;
             if(a[mid]<=y) l=mid+;
             else {
                 r=mid-;
             }
         }
         if(a[r]>y) r--;
         if(a[r]>=x&&a[r]<=y) cout<<a[r]<<endl;
         else cout<<-<<endl;
     }
 }

D

应该是最大子段和的加强版吧，把最大前缀和，最大后缀和，最大子区间和求出来，然后找最大值

 #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 eb emplace_back
 #define maxn 1000006
 #define eps 1e-8
 #define pi acos(-1.0)
 #define rep(k,i,j) for(int k=i;k<j;k++)
 typedef long long ll;
 typedef unsigned long long ull;

 ll maxl[],maxr[],sum[],dp[],Right;

 int main(){
     #ifndef ONLINE_JUDGE
      //   freopen("input.txt","r",stdin);
     #endif
     std::ios::sync_with_stdio(false);
     int n,m;
     cin>>n>>m;
     int num;
     int x;
     for(int i=;i<=n;i++){
         cin>>num;
         maxl[i]=dp[i]=-0x3f3f3f3f;
         Right=;
         for(int j=;j<=num;j++){
             cin>>x;
             sum[i]+=x;
             maxl[i]=max(sum[i],maxl[i]);
             Right+=x;
             dp[i]=max(dp[i],Right);
             if(Right<) Right=;
         }
         maxr[i]=Right;
     }
     ll ans=-0x3f3f3f3f;
     Right=;
     for(int i=;i<=m;i++){
         cin>>x;
         ans=max(max(ans,dp[x]),Right+maxl[x]);
         Right=max(Right+sum[x],maxr[x]);
     }
     cout<<ans<<endl;
 }

E

几何，分类讨论即可

 #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 eb emplace_back
 #define maxn 1000006
 #define eps 1e-8
 #define pi acos(-1.0)
 #define rep(k,i,j) for(int k=i;k<j;k++)
 typedef long long ll;
 typedef unsigned long long ull;

 struct Point{
     double x,y;
 }a[],h[],s,e;
 double ans;
 int p[],n,m;

 double dis(Point a, Point b) {
     return sqrt((a.x - b.x) * (a.x - b.x) + (a.y - b.y) * (a.y - b.y));
 }

 double cross(Point s, Point a, Point b) {
     return (a.x - s.x) * (b.y - s.y) - (b.x - s.x) * (a.y - s.y);
 }

 void check(Point a, Point b, Point c, Point d, int i) {
     double t1 = cross(a, c, b), t2 = cross(a, b, d), t3 = cross(c, a, d), t4 = cross(c, d, b);
     if (fabs(t1) < eps && fabs(t2) < eps) return ;
     if (fabs(dis(a, c) + dis(c, b) - dis(a, b)) < eps) {
         h[m] = c; p[m] = i; ++m; return ;
     }
     if (t1 * t2 > eps && t3 * t4 > eps) {
         h[m].x = (t1 * d.x + t2 * c.x) / (t1 + t2);
         h[m].y = (t1 * d.y + t2 * c.y) / (t1 + t2);
         p[m] = i; ++m;
     }
 }

 double getl(int st, int en, int x, int y) {
     double res; st = (st + ) % n; res = ;
     for (int i = st; i != en; i = (i + ) % n)
         res += dis(a[i], a[(i + ) % n]);
     return res + dis(h[x], a[st]) + dis(a[en], h[y]);
 }

 int main(){
     #ifndef ONLINE_JUDGE
      //   freopen("input.txt","r",stdin);
     #endif
    // std::ios::sync_with_stdio(false);
     cin>>s.x>>s.y>>e.x>>e.y>>n;
     for (int i = ; i < n; ++i) cin>>a[i].x>>a[i].y;
     for (int i = ; i < n; ++i) check(s, e, a[i], a[(i + ) % n], i);
     if (m == ) {
         if (dis(s, h[]) > dis(s, h[])) swap(h[], h[]), swap(p[], p[]);
         ans = min(getl(p[], p[], , ), getl(p[], p[], , ));
         ans = min(ans, dis(h[], h[]) * );
         ans += dis(s, h[]) + dis(h[], e);
     }
     else ans = dis(s, e);
     printf("%.7f\n",ans);
 }