题目如下:
代码如下:
package huawei;
public final class Demo {
public static boolean isInTriangle(POINT A, POINT B, POINT C, POINT P) {
double ABC = triAngleArea(A, B, C);
double ABp = triAngleArea(A, B, P);
double ACp = triAngleArea(A, C, P);
double BCp = triAngleArea(B, C, P);
if (ABC == ABp + ACp + BCp) {// 若面积之和等于原三角形面积,证明点在三角形内
return true;
} else {
return false;
}
}
private static double triAngleArea(POINT A, POINT B, POINT C) {// 由三个点计算这三个点组成三角形面积
double result = Math.abs((A.x * B.y + B.x * C.y + C.x * A.y - B.x * A.y - C.x * B.y - A.x * C.y) / 2.0D);
return result;
}
}