Rescue The Princess（2013年山东省第四届ACM大学生程序设计竞赛A题）

http://acm.sdut.edu.cn/sdutoj/showproblem.php?pid=2603&cid=1178

明白了题的题意但是不会敲，问了队里比我厉害的大神才懂

这个是极坐标的做法

#include<stdio.h>
#include<math.h>
#include<string.h>
#define PI acos(-1.0)
int main()
{
    int n;
    double x1,x2,x3,y1,y2,y3,l;
    scanf("%d",&n);
    for(int i = 1 ; i <= n ; i++)
    {
        scanf("%lf %lf %lf %lf",&x1,&y1,&x2,&y2);
        double du = atan2((y2-y1),(x2-x1));
        l = sqrt((y2-y1)*(y2-y1)+(x2-x1)*(x2-x1));
        x3 = x1 + l*cos(du+PI/3);
        y3 = y1 + l*sin(du+PI/3);
        printf("(%.2lf,%.2lf)\n",x3,y3);
    }
    return 0;
}

还有这个是FMH做的三角形坐标，用的向量什么的，看着有些复杂，不过其实知识点了解了之后就好懂了，就是要记住就不太难了

#include<cstdio>
//#include<cstring>
//#include<algorithm>
//#include<iostream>
#include<cmath>
//#include<complex>
using namespace std;
#define PI 3.1415926
struct Point
{
    double x,y;
    Point(double x=0,double y=0):x(x),y(y){}
};

typedef Point Vector;
Vector Rotate(Vector A,double rad){
   return Vector (A.x*cos(rad)-A.y*sin(rad),A.x*sin(rad)+A.y*cos(rad));
}//旋转，rad是弧度

//double Cross(Vector A,Vector B){ return A.x*B.y-A.y*B.x;}//叉积

Vector operator - (Point A,Point B) {return Vector(A.x-B.x,A.y-B.y);}
//Vector operator + (Vector A,Vector B) {return Vector(A.x+B.x,A.y-B.y);}
//Vector operator * (Vector A,double p) {return Vector(A.x*p,A.y*p);}

int main()
{
    int t;
    Point A,B,D;
    Vector C;
    scanf("%d",&t);
    while(t--)
    {
        scanf("%lf %lf %lf%lf",&A.x,&A.y,&B.x,&B.y);
        Vector v1=B-A;//AB向量
        C=Rotate(v1,PI/3);//旋转之后的向量
        printf("(%.2lf,%.2lf)\n",C.x+A.x,C.y+A.y);
    }
    return 0;
}