uva 11437 - Triangle Fun(几何)

题目链接：uva 11437 - Triangle Fun

#include <cstdio>#include <cstring>#include <cstdlib>#include <cmath>#include <algorithm>using namespace std;const int maxn = 3;struct point {double x, y;void input() { scanf("%lf%lf", &x, &y);}}p[maxn], m[maxn];struct line {double A, B, C;}l[maxn];point getPoint(point a, point b) {double x = a.x + (b.x - a.x) * 2 / 3;double y = a.y + (b.y - a.y) * 2 / 3;return (point){x, y};}line getLine (point a, point b) {double A = b.y - a.y;double B = a.x - b.x;double C = a.y * b.x - a.x * b.y;return (line){A, B, C};}point getCpoint(line a, line b) {double x = (a.B * b.C - a.C * b.B) / (a.A * b.B - b.A * a.B);double y = (b.C * a.A - a.C * b.A) / (a.B * b.A - a.A * b.B);return (point){x, y};}double area(point a, point b, point c) {double A = a.x * b.y - b.x * a.y;double B = b.x * c.y - c.x * b.y;double C = c.x * a.y - a.x * c.y;return fabs((A + B + C) / 2);}int main () {int cas;scanf("%d", &cas);while (cas--) {for (int i = 0; i < maxn; i++)p[i].input();for (int i = 0; i < maxn; i++)m[i] = getPoint(p[i], p[(i+1) % maxn]);for (int i = 0; i < maxn; i++)l[i] = getLine(p[i], m[(i+1) % maxn]);for (int i = 0; i < maxn; i++)p[i] = getCpoint(l[i], l[(i+1) % maxn]);printf("%.0lf\n", area(p[0], p[1], p[2]));}return 0;}