def __PROGTEST__
#include <stdio.h>
#include <assert.h>
#include <math.h>
#include <float.h>
#include <stdlib.h>
#define TRIANGLE_INVALID   (-1)
#define POINT_OUTSIDE      0
#define POINT_EDGE         1
#define POINT_INSIDE       2
#endif /* __PROGTEST__ */

int PointTriangle ( double x,  double y,
                    double xA, double yA,   /*A*/
                    double xB, double yB,   /*B*/
                    double xC, double yC )  /*C*/
 {

double a, b, v0x, v0y, v1x, v1y, v2x, v2y, soucin1, soucin2, soucin3, soucin4, soucin5, vzdalenost1, vzdalenost2, vzdalenost3, vzdalenostAbod, vzdalenostBbod, vzdalenostCbod;


    /*lezi uvnitr?*/
    v0x=xC-xA;
    v0y=yC-yA;

    v1x=xB-xA;
    v1y=yB-yA;

    v2x=x-xA;
    v2y=y-yA;

    soucin1=(v0x*v0x)-(v0y*v0y);
    soucin2=(v0x*v1x)-(v0y*v1y);
    soucin3=(v0x*v2x)-(v0y*v2y);
    soucin4=(v1x*v1x)-(v1y*v1y);
    soucin5=(v1x*v2x)-(v1y*v2y);

    a=(soucin4*soucin3-soucin2*soucin5)/(soucin1*soucin4-soucin2*soucin2);
    b=(soucin1*soucin5-soucin2*soucin3)/(soucin1*soucin4-soucin2*soucin2);


    /*exsituje trojuhelnik?*/
    vzdalenost1= sqrt((xA-xB)*(xA-xB)+(yA-yB)*(yA-yB)); /*AB*/
    vzdalenost2= sqrt((xB-xC)*(xB-xC)+(yB-yC)*(yB-yC)); /*BC*/
    vzdalenost3= sqrt((xA-xC)*(xA-xC)+(yA-yC)*(yA-yC)); /*AC*/

    /*vzdalenost bodu od A/B/C*/
    vzdalenostAbod= sqrt((xA-x)*(xA-x)+(yA-y)*(yA-y)); /*bod A od P*/

    vzdalenostBbod= sqrt((xB-x)*(xB-x)+(yB-y)*(yB-y)); /*bod B od P*/

    vzdalenostCbod= sqrt((xC-x)*(xC-x)+(yC-y)*(yC-y)); /*bod C od P*/


    if (vzdalenost1<(vzdalenost2+vzdalenost3) || vzdalenost2<(vzdalenost1+vzdalenost3) || vzdalenost3<(vzdalenost2+vzdalenost1)){
        return (-1);
    }

    else if (vzdalenostAbod+vzdalenostBbod==vzdalenost1 || vzdalenostBbod+vzdalenostCbod==vzdalenost2 || vzdalenostAbod+vzdalenostCbod==vzdalenost3){
        return 1;
    }

    else if (a>=0 && b>=0 && (a+b)<1){
        return 2;
    }

    else
        return 0;

 }

#ifndef __PROGTEST__
int main ( int argc, char * argv [] )
 {
   assert ( PointTriangle ( 5, 5,
                            0, 0,
                            10, 0,
                            5, 10 ) == POINT_INSIDE );
   assert ( PointTriangle ( 0, 5,
                            0, 0,
                            10, 0,
                            5, 10 ) == POINT_OUTSIDE );
   assert ( PointTriangle ( 0.09, 0.02,
                            0, 0,
                            0.1, 0,
                            0.05, 0.1 ) == POINT_EDGE );
   assert ( PointTriangle ( 3, 5,
                            0, 0,
                            10, 0,
                            10, 0 ) == TRIANGLE_INVALID );
   assert ( PointTriangle ( 0, 0,
                            -330, 934,
                            701, -548,
                            -2185.8, 3601.6 ) == TRIANGLE_INVALID );
   return 0;
 }
#endif /* __PROGTEST__ */