hdu2080

计算两点关于原点夹角，数学

 1 #include<stdio.h>
 2 #include<math.h>
 3 double len(double x1,double y1,double x2,double y2){
 4     return sqrt((x1-x2)*(x1-x2)+(y1-y2)*(y1-y2));
 5 }
 6 int main(){
 7     int T;
 8     while(scanf("%d",&T)!=EOF){
 9         for(int q=1;q<=T;q++){
10             double x1,y1,x2,y2;
11             double a,b,c;
12             scanf("%lf%lf%lf%lf",&x1,&y1,&x2,&y2);
13             a=len(0,0,x1,y1);
14             b=len(0,0,x2,y2);
15             c=len(x1,y1,x2,y2);
16             double cos1=(a*a+b*b-c*c)/(2*a*b);
17             double t=acos(cos1)*180/3.14159;
18             printf("%.2lf\n",t);
19         }
20     }
21     return 0;
22 }
View Code

 

hdu2081

模拟

 1 #include<stdio.h>
 2 
 3 int main(){
 4     int N;
 5     while(scanf("%d",&N)!=EOF){
 6         for(int q=1;q<=N;q++){
 7             char a[12];
 8             scanf("%s",a);
 9             printf("6");
10             for(int i=6;i<=10;i++)printf("%c",a[i]);
11             printf("\n");
12             getchar();
13         }
14     }
15     return 0;
16 }
View Code