OpenSoure_Repos/TheAlgorithms-C-Plus-Plus
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re-enable the commented algorithm

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Krishna Vedala 2020-05-28 14:07:27 -04:00
parent be997d3da3
commit 9da5e0cecf
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1 changed files with 44 additions and 37 deletions
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81
others/smallest-circle.cpp
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@ -20,7 +20,7 @@ struct Point {
* \param [in] a absicca (default = 0.0) * \param [in] a absicca (default = 0.0)
* \param [in] b ordinate (default = 0.0) * \param [in] b ordinate (default = 0.0)
*/ */
Point(double a = 0.0, double b = 0.0) { Point(double a = 0.f, double b = 0.f) {
x = a; x = a;
y = b; y = b;
} }
@ -90,38 +90,45 @@ double circle(const std::vector<Point> &P) {
Point C; Point C;
Point minC; Point minC;
/* This code is invalid and does not give correct result for TEST 3 /* This code is invalid and does not give correct result for TEST 3 */
// for each point in the list // for each point in the list
for (size_t i = 0; i < P.size() - 2; i++) for (size_t i = 0; i < P.size() - 2; i++)
// for every subsequent point in the list
for (size_t j = i + 1; j < P.size(); j++)
// for every subsequent point in the list // for every subsequent point in the list
for (size_t j = i + 1; j < P.size(); j++) for (size_t k = j + 1; k < P.size(); k++) {
// for every subsequent point in the list // here, we now have picked three points from the given set of
for (size_t k = j + 1; k < P.size(); k++) { // points that we can use
// here, we now have picked three points from the given set // viz., P[i], P[j] and P[k]
of C.x = -0.5 * ((P[i].y * (P[j].x * P[j].x + P[j].y * P[j].y -
// points that we can use P[k].x * P[k].x - P[k].y * P[k].y) +
// viz., P[i], P[j] and P[k] P[j].y * (P[k].x * P[k].x + P[k].y * P[k].y -
C.x = -0.5 * ((P[i].y * (P[j].x * P[j].x + P[j].y * P[j].y - P[i].x * P[i].x - P[i].y * P[i].y) +
P[k].x * P[k].x - P[k].y * P[k].y) P[k].y * (P[i].x * P[i].x + P[i].y * P[i].y -
+ P[j].y * (P[k].x * P[k].x + P[k].y * P[k].y - P[i].x * P[i].x - P[i].y P[j].x * P[j].x - P[j].y * P[j].y)) /
* P[i].y) + P[k].y * (P[i].x * P[i].x + P[i].y * P[i].y - P[j].x * P[j].x (P[i].x * (P[j].y - P[k].y) +
- P[j].y * P[j].y)) / (P[i].x * (P[j].y - P[k].y) + P[j].x * (P[k].y - P[j].x * (P[k].y - P[i].y) +
P[i].y) + P[k].x * (P[i].y - P[j].y))); C.y = 0.5 * ((P[i].x * (P[j].x * P[k].x * (P[i].y - P[j].y)));
P[j].x + P[j].y * P[j].y - P[k].x * P[k].x - P[k].y * P[k].y) + P[j].x * C.y = 0.5 * ((P[i].x * (P[j].x * P[j].x + P[j].y * P[j].y -
(P[k].x * P[k].x + P[k].y * P[k].y - P[i].x * P[i].x - P[i].y * P[i].y) + P[k].x * P[k].x - P[k].y * P[k].y) +
P[k].x * (P[i].x * P[i].x + P[i].y * P[i].y - P[j].x * (P[k].x * P[k].x + P[k].y * P[k].y -
P[j].x * P[j].x - P[j].y * P[j].y)) P[i].x * P[i].x - P[i].y * P[i].y) +
/ (P[i].x * (P[j].y - P[k].y) + P[j].x * (P[k].y - P[i].y) + P[k].x * P[k].x * (P[i].x * P[i].x + P[i].y * P[i].y -
(P[i].y - P[j].y))); R = (LenghtLine(P[i], P[j]) * LenghtLine(P[j], P[k]) P[j].x * P[j].x - P[j].y * P[j].y)) /
* LenghtLine(P[k], P[i])) / (4 * TriangleArea(P[i], P[j], P[k])); if (P[i].x * (P[j].y - P[k].y) +
(!PointInCircle(P, C, R)) { continue; P[j].x * (P[k].y - P[i].y) +
} P[k].x * (P[i].y - P[j].y)));
if (R <= minR) { R = (LenghtLine(P[i], P[j]) * LenghtLine(P[j], P[k]) *
minR = R; LenghtLine(P[k], P[i])) /
minC = C; (4 * TriangleArea(P[i], P[j], P[k]));
} if (!PointInCircle(P, C, R)) {
continue;
} }
*/ if (R <= minR) {
minR = R;
minC = C;
}
}
// for each point in the list // for each point in the list
for (size_t i = 0; i < P.size() - 1; i++) for (size_t i = 0; i < P.size() - 1; i++)
@ -145,42 +152,42 @@ double circle(const std::vector<Point> &P) {
/** Test case: result should be: /** Test case: result should be:
* \n Circle with * \n Circle with
* \n radius 3.318493136080724 * \n radius 3.318493136080724
* \n centre at (3.0454545454545454 1.3181818181818181) * \n centre at (3.0454545454545454, 1.3181818181818181)
*/ */
void test() { void test() {
std::vector<Point> Pv(5);
Pv.push_back(Point(0, 0)); Pv.push_back(Point(0, 0));
Pv.push_back(Point(1, 3)); Pv.push_back(Point(1, 3));
Pv.push_back(Point(4, 1)); Pv.push_back(Point(4, 1));
Pv.push_back(Point(5, 4)); Pv.push_back(Point(5, 4));
Pv.push_back(Point(3, -2)); Pv.push_back(Point(3, -2));
std::vector<Point> Pv;
std::cout << circle(Pv) << std::endl; std::cout << circle(Pv) << std::endl;
} }
/** Test case: result should be: /** Test case: result should be:
* \n Circle with * \n Circle with
* \n radius 1.4142135623730951 * \n radius 1.4142135623730951
* \n centre at (1.0 1.0) * \n centre at (1.0, 1.0)
*/ */
void test2() { void test2() {
std::vector<Point> Pv(4);
Pv.push_back(Point(0, 0)); Pv.push_back(Point(0, 0));
Pv.push_back(Point(0, 2)); Pv.push_back(Point(0, 2));
Pv.push_back(Point(2, 2)); Pv.push_back(Point(2, 2));
Pv.push_back(Point(2, 0)); Pv.push_back(Point(2, 0));
std::vector<Point> Pv;
std::cout << circle(Pv) << std::endl; std::cout << circle(Pv) << std::endl;
} }
/** Test case: result should be: /** Test case: result should be:
* \n Circle with * \n Circle with
* \n radius 1.821078397711709 * \n radius 1.821078397711709
* \n centre at (2.142857142857143 1.7857142857142856) * \n centre at (2.142857142857143, 1.7857142857142856)
*/ */
void test3() { void test3() {
std::vector<Point> Pv(3);
Pv.push_back(Point(0.5, 1)); Pv.push_back(Point(0.5, 1));
Pv.push_back(Point(3.5, 3)); Pv.push_back(Point(3.5, 3));
Pv.push_back(Point(2.5, 0)); Pv.push_back(Point(2.5, 0));
std::vector<Point> Pv;
std::cout << circle(Pv) << std::endl; std::cout << circle(Pv) << std::endl;
} }