package main import . "fmt" import . "math" func main() { var xa,ya,xb,yb float64 Scan(&xa,&ya,&xb,&yb) var mind float64 = 1e9 var ans float64 for i := 0; i <= 1e7; i++ { yp := (float64(i)/1e7)*Abs(ya-yb)+Min(ya,yb) d := Hypot(xa,ya-yp)+Hypot(xb,yb-yp) if d < mind { ans,mind = yp,d } } Println(ans) }