【HDOJ】1071 The area
数学题，先求抛物线和直线的系数，再利用积分公式求面积。
1 #include <stdio.h> 2 #include <math.h> 3 4 int main() { 5 double x1, x2, x3, y1, y2, y3; 6 double a, b, c, k, m; 7 double s1, s2; 8 int case_n; 9 10 scanf("%d", &case_n); 11 12 while (case_n--) { 13 scanf("%lf%lf%lf%lf%lf%lf", &x1,&y1, &x2,&y2, &x3,&y3); 14 a = (y2-y1) / pow(x2-x1, 2); 15 b = -2*a*x1; 16 c = a*x1*x1+y1; 17 k = (y2-y3) / (x2-x3); 18 m = y3 - k*x3; 19 s1 = a*pow(x2, 3)/3 + (b-k)*x2*x2/2 + (c-m)*x2; 20 s2 = a*pow(x3, 3)/3 + (b-k)*x3*x3/2 + (c-m)*x3; 21 printf("%.2lf\n", s2-s1); 22 } 23 24 return 0; 25 }
