入门水题找找灵感，题就不贴图了，都能找到，附上自己写的源代码，有一个题有点问题，以后有空再看，今天太累了

HDU 2000

#include<iostream>
using namespace std;int main(){char a,b,c;while(cin>>a>>b>>c){if((int)a>(int)b) {swap(a,b);}if((int)a>(int)c){swap(a,c);}if((int)b>(int)c){swap(b,c);}cout << a<<" "<<b<<" "<<c << endl;}return 0;
}

HDU2001

#include<iostream>
#include<cmath>
using namespace std;
int main(){double x1,x2,y1,y2;while(cin>>x1>>y1>>x2>>y2){double dx=x1-x2;double dy=y1-y2;double d=sqrt(dx*dx+dy*dy);printf("%.2lf\n",d);}return 0;
}

HDU2002

#include<iostream>
using namespace std;
const double PI=3.1415927;
int main(){double r,s;while(cin>>r){s=(4/3.0)*PI*r*r*r;printf("%.3lf\n",s);}return 0;
}

 HDU 2003

#include<iostream>
#include<cmath>
using namespace std;
int main(){double x;while(cin>>x){printf("%.2lf\n",abs(x));}return 0;
}

HDU 2004

#include<iostream>
using namespace std;
int main(){double x;while(cin>>x){if(x<0||x>100) cout << "Score is error!" << endl;else{if(x<=59) cout << "E" << endl;if(x>=60&&x<=69) cout << "D" << endl;if(x>=70&&x<=79) cout << "C" << endl;if(x>=80&&x<=89) cout << "B" << endl;if(x>=90) cout << "A" << endl;}}return 0;
}

 HDU 2005

#include<iostream>
using namespace std;
int day[]={31,28,31,30,31,30,31,31,30,31,30,31};
//闰年的定义有点麻烦
int main(){int a,b,c,days;while(scanf("%d/%d/%d",&a,&b,&c)!=EOF){days=0;if(a%400==0||(a%4==0&&a%100!=0)){day[1]=29;}else{day[1]=28;}for(int i=0;i<b-1;i++){days+=day[i];}days+=c;cout << days << endl;}return 0;
}

 HDU 2006

#include<iostream>
using namespace std;
int main(){int n;while(cin>>n){int sum=1;while(n--){int x;cin>>x;if(x%2!=0) sum*=x;}cout << sum << endl;}return 0;
}

HDU 2007

#include<iostream>using namespace std;
int main(){int m,n;while(cin>>m>>n){int x,y;x=0,y=0;if(m>n) swap(m,n);for(int i=m;i<=n;i++){if(i%2==0) x+=i*i;else y+=i*i*i;}cout << x <<" "<< y << endl;}return 0;
}

HDU 2008

#include<iostream>using namespace std;int main() {int n;int a;//负数int b;//0int c;//正数while(cin>>n&&n!=0){a=0,b=0,c=0;while(n--){double x;cin>>x;if(x==0.0) b++;if(x>0.0) c++;if(x<0.0) a++;}cout << a <<" "<<b<<" " <<" "<<c<< endl;}return 0;
}

HDU 2009

#include<iostream>
#include<cmath>
using namespace std;int main() {double m,n;while(cin>>n>>m){double sum=n;for(int i=1;i<m;i++){sum+=sqrt(n);n=sqrt(n);}printf("%.2lf\n",sum);}return 0;
}

HDU 2010

#include<iostream>using namespace std;
//水仙花数
int main() {int m,n;while(cin>>m>>n){//标记位数int a,b,c;int count=0;for(int i=m;i<=n;i++){a=i/100;b=(i/10)%10;c=i%10;int x=a*a*a+b*b*b+c*c*c;if(a*a*a+b*b*b+c*c*c==i) {count=1;cout << x << " ";}}if(count==0) cout << "no" << endl;else cout<<endl;}return 0;
}