Educational Codeforces Round 53 (Rated for Div. 2)

http://codeforces.com/contest/1073

A. Diverse Substring

 #include <bits/stdc++.h>
 using namespace std;
 #define ll long long
 #define minv 1e-6
 #define inf 1e9
 #define pi 3.1415926536
 #define nl 2.7182818284
 const ll mod=1e9+;//
 const int maxn=1e3+;

 char s[maxn];

 int main()
 {
     int n,i;
     scanf("%d",&n);
     scanf("%s",s);
     for (i=;i<=n-;i++)
         if (s[i]!=s[i+])
             break;
     if (i==n-)
         printf("NO");
     else
     {
         printf("YES\n");
         printf("%c%c",s[i],s[i+]);
     }
     return ;
 }

B. Vasya and Books

 #include <iostream>
 #include <cstdio>
 using namespace std;
 const int maxn=2e5+;

 int f[maxn];

 int main()
 {
     int n,a,v=,i;
     scanf("%d",&n);
     for (i=;i<=n;i++)
     {
         scanf("%d",&a);
         f[a]=i;
     }
     for (i=;i<=n;i++)
     {
         scanf("%d",&a);
         if (i!=)
             printf(" ");
         if (f[a]<v)
             printf("");
         else
             printf("%d",f[a]-v);
         v=max(f[a],v);
     }
     return ;
 }

C. Vasya and Robot

奇偶，负数取模

 #include <bits/stdc++.h>
 using namespace std;
 #define ll long long
 const int maxn=2e5+;
 const ll inf=1e9;

 int px[maxn],py[maxn];

 int main()
 {
     char c;
     int n,x,y,ax,ay,i,l,r,m,re;
     scanf("%d\n",&n);
     for (i=;i<=n;i++)
     {
         scanf("%c",&c);
         if (c=='U')
             x=,y=;
         else if (c=='D')
             x=,y=-;
         else if (c=='L')
             x=-,y=;
         else
             x=,y=;
         px[i]=px[i-]+x;
         py[i]=py[i-]+y;
     }
     scanf("%d%d",&ax,&ay);
     if (px[n]==ax && py[n]==ay)
     {
         printf("");
         return ;
     }
     if (abs(ax+ay+n)%==)
     {
         printf("-1");
         return ;
     }
     re=inf;
     for (i=;i<=n;i++)
     {
         l=i;
         r=n;
         while (l<=r)
         {
             m=(l+r)>>;
             ///change [i,m] ; use [1,i-1] [m+1,n]
             if (m-i+>=abs(px[i-]+px[n]-px[m]-ax)+abs(py[i-]+py[n]-py[m]-ay))
                 r=m-;
             else
                 l=m+;
         }
         if (l!=n+)
             re=min(re,l-i+);
     }
     if (re==inf)
         re=-;
     printf("%d",re);
     return ;
 }

D. Berland Fair

 #include <bits/stdc++.h>
 using namespace std;
 #define ll long long
 const int maxn=2e5+;

 int nex[maxn],a[maxn];

 int main()
 {
     int n,i,j,g;
     ll m,tot=,num=;
     scanf("%d%lld",&n,&m);

     for (i=;i<n;i++)
         scanf("%d",&a[i]),tot+=a[i];
     for (i=;i<n;i++)
         nex[i]=(i+)%n;
     g=n;
     i=;
     j=n-;
     while (nex[i]!=i)
     {
         num+=m/tot*g;
         m%=tot;
         while (nex[i]!=i)
         {
             if (a[i]<=m)
             {
                 m-=a[i];
                 num++;
                 j=i;
             }
             else
             {
                 nex[j]=nex[i];
                 tot-=a[i];
                 g--;
             }
             i=nex[i];
             if (m>=tot)
                 break;
         }
     }
     num+=m/a[i];
     cout<<num;
     return ;
 }
 /*
 1 100
 1

 3 1000
 1 2 100
 */

E. Segment Sum

代码是错的，以待后续埋坑

 #include <bits/stdc++.h>
 using namespace std;
 #define ll long long
 const ll mod=;
 const double minv=1e-;

 ll sum=,shi[],k,f[][];

 void work(ll a,int w,int g,int hav,ll num,int ori,int cond)
 {
     int s,gg,i,j,c;
     if (a==)
         return;
     s=a/shi[w];
     for (i=;i<=s;i++)
     {
         gg=g-(!((hav>>i) & ) && (!(i== && ori==)));
         if (gg>=)
         {
             if (i<s)
             {
                 /**
                 这一位选的是i，
                 除去这一位，还有w位，
                 从gg个数中选j个数作为需要添加的数(之前没出现过的)，
                 每一位都有k-gg+j种选择
                 **/
                 f[][]=;
                 for (j=;j<=w;j++)
                 {
                     f[j][]=f[j-][]*(k-gg)%mod;
                     ///already k-gg numbers
                     sum=(sum+f[j-][]* sum of k-gg numbers )%mod;

                     for (c=;c<=min(gg,j);c++)

                             sum=(sum+f[j-][c]* k-gg+c numbers + f[j-][c-]* any number(random average of gg numbers))

                         f[j][c]=(f[j-][c]*(k-gg+c)+f[j-][c-]*(-(k-gg+c-)))%mod;
                 }
                 for (c=;c<=min(gg,w);c++)
                     sum=(sum+f[w][c]*cond)%mod;

                 ///geshu
 //                f[0][0]=1;
 //                for (j=1;j<=w;j++)
 //                {
 //                    f[j][0]=f[j-1][0]*(k-gg)%mod;
 //                    for (c=1;c<=min(gg,j);c++)
 //                        f[j][c]=(f[j-1][c]*(k-gg+c)+f[j-1][c-1]*(10-(k-gg+c-1)))%mod;
 //                }
 //                for (c=0;c<=min(gg,w);c++)
 //                    sum=(sum+f[w][c]*cond)%mod;
             }
             else
                 work(a%shi[w],w-,gg,hav|(<<i),ori&(i==),cond);
         }
     }
 }

 int main()
 {
     ll l,r;
     int i,w;
     scanf("%lld%lld%d",&l,&r,&k);
     shi[]=;
     for (i=;i<=;i++)
         shi[i]=shi[i-]*;

     w=log(r+minv)/log();
     work(r,w,k,,,,);
     if (l!=)
     {
         w=log(l-+minv)/log();///l=1???
         work(l-,w,k,,,,-);
     }
     printf("%lld",(sum+mod)%mod);
     return ;
 }