Buggy python submission (verdict: Runtime Error):
import math
n = int(raw_input())
for i in range(n)
    x1, y1, x2, y2, x3, y3 = map(float, raw_input().split())
    a = math.sqrt((x1-x2)**2+(y1-y2)**2)
    b = math.sqrt((x1-x3)**2+(y1-y3)**2)
    c = math.sqrt((x2-x3)**2+(y2-y3)**2)
    s = (a+b+c)/2
    ss = math.sqrt(s*(s-a)*(s-b)*(s-c))
    sina = 2*ss/b/c
 
    r = a/sina/2

    a = a*a
    b = b*b
    c = c*c
    px = (a*(b+c-a)*x3 + b*(a+c-b)*x2+c*(a+b-c)*x1)/16/ss**2
    py =(a*(b+c-a)*y3 + b*(a+c-b)*y2+c*(a+b-c)*y1)/16/ss**2

    print "%.3f %.3f %.3f" % (px, py, r)

Fixed submission:
import math
n = int(raw_input())
for i in range(n):
    x1, y1, x2, y2, x3, y3 = map(float, raw_input().split())
    a = math.sqrt((x1-x2)**2+(y1-y2)**2)
    b = math.sqrt((x1-x3)**2+(y1-y3)**2)
    c = math.sqrt((x2-x3)**2+(y2-y3)**2)
    s = (a+b+c)/2
    ss = math.sqrt(s*(s-a)*(s-b)*(s-c))
    sina = 2*ss/b/c
 
    r = a/sina/2

    a = a*a
    b = b*b
    c = c*c
    px = (a*(b+c-a)*x3 + b*(a+c-b)*x2+c*(a+b-c)*x1)/16/ss**2
    py =(a*(b+c-a)*y3 + b*(a+c-b)*y2+c*(a+b-c)*y1)/16/ss**2

    print "%.3f %.3f %.3f" % (px, py, r)

Buggy python submission (verdict: Runtime Error):
#include <stdio.h>
#include <math.h>

int main(void){
	int n;
	double x1,y1,x2,y2,x3,y3,a,b,c,s,ss,sina,r,px,py;
	scanf("%d",&n);
	while (n--){
		scanf("%lf %lf %lf %lf %lf %lf",&x1,&y1,&x2,&y2,&x3,&y3);
		a = sqrt(pow(x1-x2,2)+pow(y1-y2,2));
		b = sqrt(pow(x1-x3,2)+pow(y1-y3,2));
		c = sqrt(pow(x2-x3,2)+pow(y2-y3,2));
		s = (a+b+c)/2;
		ss = sqrt(s*(s-a)*(s-b)*(s-c));
		sina = 2*ss/b/c;
		r = a/sina/2;
		a = a*a; b = b*b; c = c*c;
		px = (a*(b+c-a)*x3 + b*(a+c-b)*x2+c*(a+b-c)*x1)/16/pow(ss,2);
		py = (a*(b+c-a)*y3 + b*(a+c-b)*y2+c*(a+b-c)*y1)/16/pow(ss,2);
		printf("%.3f %.3f %.3f",px, py, r);
	}
}

Fixed submission:
import math
n = int(raw_input())
for i in range(n):
    x1, y1, x2, y2, x3, y3 = map(float, raw_input().split())
    a = math.sqrt((x1-x2)**2+(y1-y2)**2)
    b = math.sqrt((x1-x3)**2+(y1-y3)**2)
    c = math.sqrt((x2-x3)**2+(y2-y3)**2)
    s = (a+b+c)/2
    ss = math.sqrt(s*(s-a)*(s-b)*(s-c))
    sina = 2*ss/b/c
 
    r = a/sina/2

    a = a*a
    b = b*b
    c = c*c
    px = (a*(b+c-a)*x3 + b*(a+c-b)*x2+c*(a+b-c)*x1)/16/ss**2
    py =(a*(b+c-a)*y3 + b*(a+c-b)*y2+c*(a+b-c)*y1)/16/ss**2

    print "%.3f %.3f %.3f" % (px, py, r)

Buggy python submission (verdict: Runtime Error):
#include <stdio.h>
#include <math.h>

int main(void){
	int n;
	double x1,y1,x2,y2,x3,y3,a,b,c,s,ss,sina,r,px,py;
	scanf("%d",&n);
	while (n--){
		scanf("%lf %lf %lf %lf %lf %lf",&x1,&y1,&x2,&y2,&x3,&y3);
		a = sqrt(pow(x1-x2,2)+pow(y1-y2,2));
		b = sqrt(pow(x1-x3,2)+pow(y1-y3,2));
		c = sqrt(pow(x2-x3,2)+pow(y2-y3,2));
		s = (a+b+c)/2;
		ss = sqrt(s*(s-a)*(s-b)*(s-c));
		sina = 2*ss/b/c;
		r = a/sina/2;
		a = a*a; b = b*b; c = c*c;
		px = (a*(b+c-a)*x3 + b*(a+c-b)*x2+c*(a+b-c)*x1)/16/pow(ss,2);
		py = (a*(b+c-a)*y3 + b*(a+c-b)*y2+c*(a+b-c)*y1)/16/pow(ss,2);
		printf("%.3f %.3f %.3f\n",px, py, r);
	}
}

Fixed submission:
import math
n = int(raw_input())
for i in range(n):
    x1, y1, x2, y2, x3, y3 = map(float, raw_input().split())
    a = math.sqrt((x1-x2)**2+(y1-y2)**2)
    b = math.sqrt((x1-x3)**2+(y1-y3)**2)
    c = math.sqrt((x2-x3)**2+(y2-y3)**2)
    s = (a+b+c)/2
    ss = math.sqrt(s*(s-a)*(s-b)*(s-c))
    sina = 2*ss/b/c
 
    r = a/sina/2

    a = a*a
    b = b*b
    c = c*c
    px = (a*(b+c-a)*x3 + b*(a+c-b)*x2+c*(a+b-c)*x1)/16/ss**2
    py =(a*(b+c-a)*y3 + b*(a+c-b)*y2+c*(a+b-c)*y1)/16/ss**2

    print "%.3f %.3f %.3f" % (px, py, r)

Buggy python submission (verdict: Runtime Error):
#include <stdio.h>
#include <math.h>

int main(void){
	int n;
	double x1,y1,x2,y2,x3,y3,a,b,c,s,ss,sina,r,px,py;
	scanf("%d",&n);
	while (n--){
		scanf("%lf %lf %lf %lf %lf %lf",&x1,&y1,&x2,&y2,&x3,&y3);
		a = sqrt(pow(x1-x2,2)+pow(y1-y2,2));
		b = sqrt(pow(x1-x3,2)+pow(y1-y3,2));
		c = sqrt(pow(x2-x3,2)+pow(y2-y3,2));
		s = (a+b+c)/2;
		ss = sqrt(s*(s-a)*(s-b)*(s-c));
		sina = 2*ss/b/c;
		r = a/sina/2;
		a = a*a; b = b*b; c = c*c;
		px = (a*(b+c-a)*x3 + b*(a+c-b)*x2+c*(a+b-c)*x1)/16/pow(ss,2);
		py = (a*(b+c-a)*y3 + b*(a+c-b)*y2+c*(a+b-c)*y1)/16/pow(ss,2);
		printf("%.3f %.3f %.3f\n", px, py, r);
	}
	return 0;
}

Fixed submission:
import math
n = int(raw_input())
for i in range(n):
    x1, y1, x2, y2, x3, y3 = map(float, raw_input().split())
    a = math.sqrt((x1-x2)**2+(y1-y2)**2)
    b = math.sqrt((x1-x3)**2+(y1-y3)**2)
    c = math.sqrt((x2-x3)**2+(y2-y3)**2)
    s = (a+b+c)/2
    ss = math.sqrt(s*(s-a)*(s-b)*(s-c))
    sina = 2*ss/b/c
 
    r = a/sina/2

    a = a*a
    b = b*b
    c = c*c
    px = (a*(b+c-a)*x3 + b*(a+c-b)*x2+c*(a+b-c)*x1)/16/ss**2
    py =(a*(b+c-a)*y3 + b*(a+c-b)*y2+c*(a+b-c)*y1)/16/ss**2

    print "%.3f %.3f %.3f" % (px, py, r)