Cf round #273 div.2

Click round #273 div.2.

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Problem A initial bet

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It's easy. For the first time, I had a question with CF in 10 minutes.

Judge the average, and note that B is positive

 1 #include<iostream> 2 using namespace std; 3 int main() 4 { 5     int res = 0,n; 6     for(int i = 0; i < 5; i++) 7     { 8         cin>>n; 9         res += n;10     }11     int b = res / 5;12     if(res % 5 == 0 && b)13         cout<<b<<endl;14     else cout<<"-1"<<endl;15     return 0;16 }

 

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Problem B random teams

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When Max is used, M-1 group are m-1)

In min, the split is equal to N/m in each group, and the remaining n % m is evenly distributed to N % m, that is, before (m-N % m) the Group is N/m, and the (N % m) group is (N/m + 1)

 1 #include<iostream> 2 #include<cstdio> 3 using namespace std; 4 long long pan(long long x) 5 { 6     return x*(x-1)/2; 7 } 8 int main() 9 {10     //freopen("input.txt","r",stdin);11     long long n,m;12     long long kmin,kmax;13     cin>>n>>m;14     kmax = pan(n-m+1);15     kmin = (m - (n%m))*pan(n/m) + (n%m)*pan(n/m+1);16     cout<<kmin<<" "<<kmax<<endl;17 18     return 0;19 }

 

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Problem C table decorations

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 1 #include<cstdio> 2 #include<algorithm> 3 using namespace std; 4 long long a[3]; 5  6 int main() 7 { 8     scanf("%d%d%d",&a[0],&a[1],&a[2]); 9     sort(a,a+3);10     printf("%d\n",min(a[0]+a[1],(a[0]+a[1]+a[2])/3));11     return 0;12 }

 

Cf round #273 div.2