UVA 10250-The Other Two Trees

题目大意：其实就是告诉正方形对点的坐标，求出另外俩个点

解题思路：向量垂直且相等即可推出

#include <stdio.h>#include <iostream>using namespace std;int main() {    double x1, x2, y1, y2, x3, x4, y3, y4, x0, y0;    while( scanf("%lf%lf%lf%lf", &x1, &y1, &x2, &y2) != EOF) {        if(x1 == x2 && y1 == y2) {            printf("Impossible.\n");            break;        }        x0 = (x1 + x2) / 2.0;        y0 = (y1 + y2) / 2.0;        x3 = x0 + y2 - y0;        y3 = y0 - x2 + x0;        x4 = x0 - y2 + y0;        y4 = y0 + x2 - x0;        printf("%.10lf %.10lf %.10lf %.10lf\n", x3, y3, x4, y4);    }    return 0;}