题解 | 点到直线距离

#include <bits/stdc++.h>
#include <cmath>
using namespace std;

struct point{
    double x,y;
    point(double A,double B){
        x=A,y=B;
    }
    point() = default;
};

struct line{
    point point_A,point_B;
    line(point A,point B){
        point_A = A,point_B = B;
    }
    line() = default;
};

double getDistance(point P, line L){
    // TODO: 计算点P到直线L的距离
    int A = L.point_B.y - L.point_A.y;
    int B = L.point_A.x - L.point_B.x;
    int C = L.point_B.x * L.point_A.y - L.point_A.x * L.point_B.y;

    double x0 = P.x;
    double y0 = P.y;

    double up = ((A * x0 + B * y0 + C) > 0 ? (A * x0 + B * y0 + C) : -(A * x0 + B * y0 + C));
    double down = sqrt(A * A + B * B);

    double shu = up / down;

    return shu;
}















































































































int main(){
    int a, b, sx, sy, tx, ty;
    cin >> a >> b >> sx >> sy >> tx >> ty;
    point A(sx, sy), B(tx, ty), C(a, b);
    line L(A, B);
    printf("%.2lf", getDistance(C, L));
    return 0;
}