Codeforces Beta Round #46 (Div. 2)

Codeforces Beta Round #46 (Div. 2)

http://codeforces.com/contest/49

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<char,int>mp;
     mp['A']++;
     mp['E']++;
     mp['I']++;
     mp['O']++;
     mp['U']++;
     mp['Y']++;
     mp['a']++;
     mp['e']++;
     mp['i']++;
     mp['o']++;
     mp['u']++;
     mp['y']++;
     string str;
     getline(cin,str);
     char ch;
     for(int i=str.length()-;i>=;i--){
         if((str[i]>='A'&&str[i]<='Z')||(str[i]>='a'&&str[i]<='z')){
             ch=str[i];
             break;
         }
     }
     if(mp[ch]) cout<<"YES"<<endl;
     else cout<<"NO"<<endl;
 }

B

模拟进制转换和运算

 #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 getmax(int a){
     int Max=;
     while(a){
         Max=max(a%,Max);
         a/=;
     }
     return Max;
 }
 
 int Change(int n,int base){
     int p=;
     int ans=;
     while(n){
         ans=ans+(n%)*p;
         n/=;
         p*=base;
     }
     return ans;
 }
 
 int main(){
     #ifndef ONLINE_JUDGE
      //   freopen("input.txt","r",stdin);
     #endif
     std::ios::sync_with_stdio(false);
     int a,b;
     cin>>a>>b;
     int base=max(getmax(a),getmax(b))+;
     int sum=Change(a,base)+Change(b,base);
     int ans=;
     while(sum){
         sum/=base;
         ans++;
     }
     cout<<ans<<endl;
 }

C

找规律

 #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);
     int n;
     cin>>n;
     cout<<n<<" ";
     for(int i=;i<n;i++) cout<<i<<" ";
 }

D

枚举第一个是0还是1，然后不断向后遍历判断，取最小值

 #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 maxn 1000005
 typedef long long ll;
 typedef unsigned long long ull;
 
 int n;
 string str;
 
 int func(int ch){
     int ans=;
     if(str[]!=ch+'') ans++;
     ch^=;
     for(int i=;i<str.length();i++){
         if(str[i]!=ch+''){
             ans++;
         }
         ch^=;
     }
     return ans;
 }
 
 int main(){
     #ifndef ONLINE_JUDGE
      //   freopen("input.txt","r",stdin);
     #endif
     std::ios::sync_with_stdio(false);
     cin>>n;
     cin>>str;
     int ans=0x3f3f3f3f;
     ans=min(ans,func());
     ans=min(ans,func());
     cout<<ans<<endl;
 }

E

区间DP

参考博客：https://blog.csdn.net/zhjchengfeng5/article/details/8201105

 #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;
 
 string s[];
 int n;
 string str[];
 int dp[][];
 bool book[][][][];
 int len[];
 
 void Init(int id){
     len[id]=s[id].length();
     rep(i,,len[id]){
         book[id][i][i][s[id][i]-'a']=;
     }
     rep(L,,len[id]+){
         int st=;
         rep(en,st+L-,len[id]){
             rep(mid,st,en){
                 rep(i,,n){
                     if(book[id][st][mid][str[i][]-'a']&&book[id][mid+][en][str[i][]-'a']){
                         book[id][st][en][str[i][]-'a']=;
                     }
                 }
             }
             st++;
         }
     }
 }
 
 int main(){
     #ifndef ONLINE_JUDGE
         freopen("input.txt","r",stdin);
     #endif
     std::ios::sync_with_stdio(false);
     cin>>s[]>>s[];
     cin>>n;
     for(int i=;i<n;i++){
         cin>>str[i];
     }
     Init(),Init();
     memset(dp,0x3f,sizeof(dp));
     dp[][]=;
     rep(mid0,,len[]){
         rep(mid1,,len[]){
             rep(st0,mid0,len[]){
                 rep(st1,mid1,len[]){
                     rep(ch,,){
                         if(book[][mid0][st0][ch]&&book[][mid1][st1][ch]){
                             dp[st0+][st1+]=min(dp[st0+][st1+],dp[mid0][mid1]+);
                         }
                     }
                 }
             }
         }
     }
     int ans=dp[len[]][len[]];
     if(ans==0x3f3f3f3f) cout<<-<<endl;
     else cout<<ans<<endl;
 }