Codeforces Round #259 (Div. 2)

A. Little Pony and Crystal Mine http://codeforces.com/contest/454/problem/A

#include<cstdio>
int main(){
    int n;
    while(~scanf("%d",&n)){
        for(int i=1;i<=n/2;i++){
            for(int j=0;j<n/2+1-i;j++){
                printf("*");
            }
            for(int j=0;j<i*2-1;j++){
                printf("D");
            }
            for(int j=0;j<n/2+1-i;j++){
                printf("*");
            }
            puts("");
        }
        for(int i=1;i<=n;i++){
            printf("D");
        }
        puts("");
        for(int i=1;i<=n/2;i++){
            for(int j=0;j<i;j++){
                printf("*");
            }
            for(int j=0;j<(n/2+1-i)*2-1;j++){
                printf("D");
            }
            for(int j=0;j<i;j++){
                printf("*");
            }
            puts("");
        }
    }
    return 0;
}

 B. Little Pony and Sort by Shift http://codeforces.com/contest/454/problem/B

#include<cstdio>
const int M=100010;
int a[M];
int main(){
    int n;
    while(~scanf("%d",&n)){
        for(int i=0;i<n;i++){
            scanf("%d",&a[i]);
        }
        int cnt=0,id;
        for(int i=0;i<n-1;i++){
            if(a[i]>a[i+1]){
                cnt++;
                id=i+1;
            }
        }
        if(cnt>1) puts("-1");
        else if(cnt<1) puts("0");
        else if(a[n-1]>a[0]) puts("-1");
        else printf("%d
",n-id);
    }
    return 0;
}

 C. Little Pony and Expected Maximum http://codeforces.com/contest/454/problem/C

#include<cstdio>
int m,n;
double mypow(int i){
    double a=i*1.0/m,res=1;
    int p=n;
    while(p){
        if(p&1) res*=a;
        a*=a;
        p>>=1;
    }
    return res;
}
int main(){
    while(~scanf("%d%d",&m,&n)){
        double ans=0;
        for(int i=1;i<=m;i++){
            ans+=i*(mypow(i)-mypow(i-1));
        }
        printf("%.12f
",ans);
    }
    return 0;
}

end