24-05-30 선분 교차 2

yuyu0830/수학/17387.cpp

@@ -0,0 +1,140 @@
+#include <iostream>
+#include <cmath>
+
+#define YES printf("1\n")
+#define NO printf("0\n")
+
+#define ERR_RANGE 1e-8
+
+using namespace std;
+
+struct Point {
+    double x, y;
+    void v(int _x, int _y) {
+        x = (double) _x;
+        y = (double) _y;
+    };
+
+    bool operator==(const Point &a) {
+        return (fabs(x - a.x) < ERR_RANGE) && (fabs(y - a.y) < ERR_RANGE);
+    }
+};
+
+struct Line {
+    Point a, b;
+    double gradient = 0.f, intercept = 0.f;
+    bool isInf = 0, isZero = 0;
+
+    void set() {
+        int x1, x2, y1, y2;
+        cin >> x1 >> x2 >> y1 >> y2;
+
+        // order by x
+        x1 < y1 ? a.v(x1, x2) : a.v(y1, y2);
+        x1 < y1 ? b.v(y1, y2) : b.v(x1, x2);
+
+        // if gradient is Zero
+        if (fabs(a.y - b.y) < ERR_RANGE) isZero = 1;
+
+        // if gradient is Infinite
+        else if (fabs(a.x - b.x) < ERR_RANGE) {
+            isInf = 1;
+            intercept = a.x;
+        }
+
+        else {
+            gradient = (a.y - b.y) / (a.x - b.x);
+            intercept = a.y - gradient * a.x;
+        }
+    }
+
+    bool isPointIn(Point p) {
+        bool ex = (p.x + ERR_RANGE >= a.x) && (p.x - ERR_RANGE <= b.x);
+        double sy = fmin(a.y, b.y), by = fmax(a.y, b.y);
+        bool ey = (p.y + ERR_RANGE >= sy) && (p.y - ERR_RANGE <= by);
+
+        return ex && ey;
+    }
+
+    void operator=(const Line &l) {
+        a = l.a;
+        b = l.b;
+        gradient = l.gradient;
+        intercept = l.intercept;
+        isZero = l.isZero;
+        isInf = l.isInf;
+    }
+};
+
+bool overlapCheck(Line a, Line b) {
+    if (a.a == b.a || a.b == b.a || a.a == b.b || a.b == b.b) {
+        YES;
+        return true;
+    }
+
+    if (a.isInf && b.isInf) {
+        double asy = fmin(a.a.y, a.b.y), aby = fmax(a.a.y, a.b.y);
+        double bsy = fmin(b.a.y, b.b.y), bby = fmax(b.a.y, b.b.y);
+        (fabs(a.intercept - b.intercept) < ERR_RANGE) && ((asy <= bby) != (aby <= bsy)) ? YES : NO;
+        return true;
+    }
+
+    if (a.isZero && b.isZero)  {
+        (fabs(a.a.x - b.a.x) < ERR_RANGE) && ((a.a.x <= b.b.x) != (a.b.x <= b.a.x)) ? YES : NO;
+        return true;
+    }
+
+    if (a.gradient && fabs(a.gradient - b.gradient) < ERR_RANGE) {
+        ((a.a.x <= b.b.x) != (a.b.x <= b.a.x)) && (fabs(a.intercept - b.intercept) < ERR_RANGE) ? YES : NO;
+        return true;
+    }
+
+    return false;
+}
+
+Point getIntersection(Line a, Line b) {
+    Point ret;
+
+    if (a.isInf || b.isInf) {
+        Line i = a.isInf ? a : b;
+        Line j = a.isInf ? b : a;
+
+        ret.x = i.intercept;
+        ret.y = j.isZero ? j.a.y : j.gradient * ret.x + j.intercept;
+    }
+
+    else if (a.isZero || b.isZero) {
+        Line i = a.isZero ? a : b;
+        Line j = a.isZero ? b : a;
+
+        ret.y = i.a.y;
+        ret.x = (ret.y - j.intercept) / j.gradient;
+    }
+
+    else {
+        ret.x = -((a.intercept - b.intercept) / (a.gradient - b.gradient));
+        ret.y = a.gradient * ret.x + a.intercept;
+    }
+
+    return ret;
+}
+
+int main() {
+    Line a, b;
+
+    a.set();
+    b.set();
+
+    //printf("a : (%.0f, %.0f), (%.0f, %.0f), %.3f, %.3f, %d, %d\n", a.a.x, a.a.y, a.b.x, a.b.y, a.gradient, a.intercept, a.isInf, a.isZero);
+    //printf("b : (%.0f, %.0f), (%.0f, %.0f), %.3f, %.3f, %d, %d\n", b.a.x, b.a.y, b.b.x, b.b.y, b.gradient, b.intercept, b.isInf, b.isZero);
+
+    // if two line's gradient is same
+    if (overlapCheck(a, b)) return 0;
+
+    Point p = getIntersection(a, b);
+
+    //printf("intersecion point : %.3f, %.3f\n", p.x, p.y);
+
+    // is intersection point on both line?
+    a.isPointIn(p) && b.isPointIn(p) ? YES : NO;
+}