Quadrilateral classification - MarisaOJ: Marisa Online Judge

Given four points

A (x_{A}, y_{A}), B (x_{B}, y_{B}), C (x_{C}, y_{C}), D (x_{D}, y_{D})

$A(x_A,y_A),B(x_B,y_B),C(x_C,y_C),D(x_D,y_D)$ , determine the type of the quadrilateral

A B C D

$ABCD$ , convex, concave or crossed. It is guaranteed that no three points are collinear. ### Input - A single line contains eight integers

x_{A}, y_{A}, x_{B}, y_{B}, x_{C}, y_{C}, x_{D}, y_{D}

$x_A,y_A,x_B,y_B,x_C,y_C,x_D,y_D$ . ### Output - Print: +

C O N V E X

$CONVEX$ if the given quadrilateral is convex. +

C O N C A V E

$CONCAVE$ if the given quadrilateral is concave. +

C R O S S E D

$CROSSED$ if the given quadrilateral is crossed. ### Constraints -

- 10^{9} \leq x, y \leq 10^{9}

$-10^9 \le x, y \le 10^9$ . ### Example Input:

00121121

$0 0 1 2 1 1 2 1$

Output:

C O N C A V E

$CONCAVE$

Geometry
	Three points
	Line segment intersection
	Line intersection
	Quadrilateral classification
	Point location
	Triangle classification
	Polygon area
	Distance to polygon
	Convex hull
	Perpendicular pairs
	Maximum quadrilateral
	Catching butterflies

Topic

Geometry

Rating

1100

Solution (0)

Solution