Codeforces Beta Round #54 (Div. 2)

Codeforces Beta Round #54 (Div. 2)

http://codeforces.com/contest/58

A

找子序列

 #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 1000005
 #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 str;
     string s="hello";
     cin>>str;
     int i=,j=;
     while(i<s.length()&&j<str.length()){
         if(s[i]==str[j]){
             i++,j++;
         }
         else{
             j++;
         }
     }
     if(i==s.length()){
         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 eb emplace_back
 #define maxn 1000005
 #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 n;
     cin>>n;
     for(int i=n;i>=;i--){
         if(n%i==){
             cout<<i<<" ";
             n=i;
         }
     }
 }

C

逆向思维，求出最多不需要修改的数量，然后减去它即可

 #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 1000005
 #define rep(k,i,j) for(int k=i;k<j;k++)
 typedef long long ll;
 typedef unsigned long long ull;

 int n;
 int a[];

 int main(){
     #ifndef ONLINE_JUDGE
        // freopen("input.txt","r",stdin);
     #endif
     std::ios::sync_with_stdio(false);
     cin>>n;
     int m;
     int ans=;
     for(int i=;i<=n;i++){
         cin>>m;
         int num=min(i,n-i+);
         m-=num;
         if(m>=){
             a[m]++;
             ans=max(ans,a[m]);
         }
     }
     cout<<n-ans<<endl;

 }

D

在每个字符串后面加上字符d，然后sort+贪心即可

 #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 1000005
 #define rep(k,i,j) for(int k=i;k<j;k++)
 typedef long long ll;
 typedef unsigned long long ull;

 int n;
 string str[];
 int book[];
 string ans[];
 string d;

 int main(){
     #ifndef ONLINE_JUDGE
        // freopen("input.txt","r",stdin);
     #endif
     std::ios::sync_with_stdio(false);
     cin>>n;
     int sum=;
     for(int i=;i<=n;i++){
         cin>>str[i];
         sum+=str[i].length();
     }
     cin>>d;
     for(int i=;i<=n;i++){
         str[i]+=d;
     }
     sum+=n/;
     int len=sum/(n/);
     int co=;
     sort(str+,str+n+);
     for(int i=;i<=n;i++){
         if(!book[i]){
             ans[co]=str[i];
             book[i]=;
             for(int j=;j<=n;j++){
                 if(!book[j]&&str[i].length()-+str[j].length()==len){
                     ans[co]+=str[j].substr(,str[j].length()-);
                     book[j]=;
                     co++;
                     break;
                 }
             }
         }
     }
     for(int i=;i<co;i++){
         cout<<ans[i]<<endl;
     }
 }

E

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 eb emplace_back
 #define maxn 1000005
 #define rep(k,i,j) for(int k=i;k<j;k++)
 typedef long long ll;
 typedef unsigned long long ull;

 ll ans1,ans2;
 ll p[];
 ll ans=;
 void dfs(ll a,ll b,ll c,ll ra,ll rb, ll jw, ll inc,ll d){
     if(inc>=ans) return;
     if(!a&&!b&&!c&&!jw){
         ans=inc;ans1=ra;ans2=rb;return;
     }
     if(!c){
         ll s=a+b+jw;
         int k=;
         while(s){
             s/=;
             k++;
         }
         dfs(,,,a*p[d]+ra,b*p[d]+rb,,inc+k,d);
         return;
     }
     if((a+b+jw)%==c%){
         dfs(a/,b/,c/,a%*p[d]+ra,b%*p[d]+rb,(a%+b%+jw)/,inc,d+);
     }
     else{
         dfs(a*+(c+-b%-jw)%,b,c,ra,rb,jw,inc+,d);
         dfs(a,b*+(c+-a%-jw)%,c,ra,rb,jw,inc+,d);
         dfs(a,b,c*+(a+b+jw)%,ra,rb,jw,inc+,d);
     }
 }

 int main(){
     #ifndef ONLINE_JUDGE
        // freopen("input.txt","r",stdin);
     #endif
     std::ios::sync_with_stdio(false);
     ll a,b,c;
     char ch;
     cin>>a>>ch>>b>>ch>>c;
     p[]=;
     for(int i=;i<=;i++) p[i]=p[i-]*;
     dfs(a,b,c,,,,,);
     cout<<ans1<<"+"<<ans2<<"="<<ans1+ans2<<endl;
 }