Educational Codeforces Round 23

A题

分析：注意两个点之间的倍数差，若为偶数则为YES，否则为NO

 #include "iostream"
 #include "cstdio"
 #include "cstring"
 #include "string"
 #include "cmath"
 using namespace std;
 int main()
 {
     int x1,y1,x2,y2;
     cin>>x1>>y1>>x2>>y2;
     int x,y;
     cin>>x>>y;
     int cnt1=x2-x1;
     int cnt2=y2-y1;
     int flag=;
     if(cnt1%x){
         flag=;
     }
     if(cnt2%y){
         flag=;
     }
     if(abs(abs(cnt1/x)-abs(cnt2/y))%){
         flag=;
     }
     if(!flag){
         cout<<"YES"<<endl;
     }else{
         cout<<"NO"<<endl;
     }
 }

B题

分析：先看只用第一个数是否满足情况，如果不行在加入第二个数，不行在加入第三个数，如此分别统计三种情况即可

 #include "iostream"
 #include "cstdio"
 #include "cstring"
 #include "string"
 #include "algorithm"
 #include "set"
 #include "vector"
 using namespace std;
 const int maxn=+;
 long long a[maxn];
 int n;
 long long solve3(long long sum){
     return (sum*(sum-)*(sum-)/);
 }
 long long solve2(long long sum){
     return (sum*(sum-)/);
 }
 int main()
 {
     cin>>n;
     for(int i=;i<n;i++)
         cin>>a[i];
     sort(a,a+n);
     set<long long>h;
     for(int i=;i<n;i++){
         h.insert(a[i]);
     }
     set<long long>::iterator it;
     vector<long long>q;
     for(it=h.begin();it!=h.end();it++){
         q.push_back(*it);
     }
     long long cnt1=,cnt2=,cnt3=;
     for(int i=;i<n;i++){
         if(a[i]==q[]){
             cnt1++;
         }else if(a[i]==q[]){
             cnt2++;
         }else if(a[i]==q[]){
             cnt3++;
         }
     }
     if(cnt1>=){
         cout<<solve3(cnt1)<<endl;
     }else if(cnt1==){
         cout<<cnt2<<endl;
     }else{
         if(cnt2>=){
             cout<<solve2(cnt2)<<endl;
         }else{
             cout<<cnt3<<endl;
         }
     }
     return ;
 }

C题

分析：因为两个数的差值最大不会超过18*9=162，所以直接暴力即可

 #include "iostream"
 #include "cstdio"
 #include "cstring"
 using namespace std;
 long long a,b;
 long long solve(long long num){
     long long ans=;
     while(num){
         long long mod=num%;
         ans+=mod;
         num/=;
     }
     return ans;
 }
 int main()
 {
     cin>>b>>a;
     long long sum=b-a;
     if(sum<=){
         cout<<""<<endl;
         return ;
     }
     long long cnt=;
     if(b-a<=){
         for(long long i=a;i<=b;i++){
             long long tt=i;
             //cout<<b-solve(tt)<<endl;
             if((i-solve(tt))>=a)
                 cnt++;
         }
         cout<<cnt<<endl;
     }else{
         for(long long i=a;i<=a+;i++){
             long long yy=i;
             if((i-solve(yy))<a)
                 cnt++;
         }
         cout<<sum-cnt+<<endl;
     }
     return ;
 }