题解 | 点到直线距离

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

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

struct line{
    point a,b;
    line(point A,point B){
        a = A,b = B;
    }
    line() = default;
};

double getDistance(point P, line L){\
    int y1 = L.a.y, y2 = L.b.y, x1 = L.a.x, x2 = L.b.x;
    int A = y2 - y1, B = x1 - x2, C = (x2 - x1) * y1 - (y2 - y1) * x1;
    int x = P.x, y = P.y;
    return abs(A * x + B * y + C) / sqrt(A * A + B *  B);
}
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;
}