added TSP (BruteForce) example

examples/TSP.cpp

 #include "cute.h"
 
 #include <algorithm>
-#include <vector>
 #include <cmath>
+#include <vector>
 using namespace cute;
 using namespace std;
 
 void nearestNeighbour();
 void twoOpt();
+void bruteForce();
 
 
 void setup()
 {
     registerAlgorithm(nearestNeighbour, "NearestNeighbour");
     registerAlgorithm(twoOpt, "2-Opt :D");
+    registerAlgorithm(bruteForce, "Brute Force!");
     setProblemSize(15);
     setPlotTheme(3);
     setPlotVisible(1, false);
@@ -26,12 +28,89 @@ float length (const Point& a, const Point& b)
     return sqrt(pow((a.x - b.x), 2) + pow((a.y - b.y), 2));
 }
 
+float circ_pythagoras(const vector<pair<int, Point>>& vec)
+{
+    float sum = 0;
+    for (size_t i = 0; i < (vec.size() - 1); ++i)
+    {
+        float distance  = length(vec[i].second, vec[i + 1].second);
+        sum            += distance;
+    }
+    if (vec.back().first != vec.front().first)
+    {
+        float distance  = length(vec.back().second, vec.front().second); //close circle
+        sum            += distance;
+    }
+    return sum;
+}
+
 namespace global
 {
     vector<Point> result;
 
 } //namespace global
 
+void plotMyVectorLines(vector<pair<int, Point>>& vec, int plot, bool loop)
+{
+    vector<Point> result;
+    result.reserve(vec.size());
+    for (auto&& p : vec)
+    {
+        result.emplace_back(p.second);
+    }
+    plotLines(result, plot, loop);
+}
+
+
+void bruteForce()
+{
+    resetPlot(0);
+    vector<Point> data = getProblemData2D();
+    plotPoints(data);
+    plotLines(data);
+
+    long long n_fac = 1;
+    for (size_t i = 1; i <= data.size() - 1; n_fac *= i++)
+    {
+    }
+    vector<pair<int, Point>> vec;
+    for (size_t i = 0; i < data.size(); ++i)
+    {
+        vec.push_back({i, data[i]});
+    }
+    vec.push_back(vec.front());
+
+    unsigned long long i = 0;
+    setStatusMessage(to_string(i) + " of " + to_string(n_fac));
+    setProgress(100 * i / n_fac);
+
+    float                    bestCirc = std::numeric_limits<float>().max();
+    vector<pair<int, Point>> bestVec  = vec;
+
+    do
+    {
+        int circ = circ_pythagoras(vec);
+        if (circ < bestCirc)
+        {
+            bestCirc = circ;
+            bestVec  = vec;
+            undo(0);
+            plotMyVectorLines(vec, 0, true);
+        }
+        if (++i % 1000 == 0)
+        {
+            setProgress(100 * i / n_fac);
+            setStatusMessage(to_string(i) + " of " + to_string(n_fac));
+        }
+    } while (cute::ok()
+             && std::prev_permutation(++vec.begin(), --vec.end(), [](pair<int, Point>& a, pair<int, Point>& b) {
+                    return a.first > b.first;
+                }));
+    setStatusMessage(to_string(i) + " of " + to_string(n_fac));
+    setProgress(100 * i / n_fac);
+    logMessage("DONE grrr");
+}
+
 
 void nearestNeighbour()
 {