Dijkstra thing is working on a sample map.

main.cpp

@@ -12,20 +12,28 @@
 #include <ftxui/dom/node.hpp>      // for Render
 #include <ftxui/screen/box.hpp>    // for ftxui
 #include <ftxui/component/component.hpp>
+#include <fmt/core.h>
+#include "map.hpp"
+#include "dbc.hpp"
 
+using std::string;
 using namespace std::chrono_literals;
 
-std::array<std::string, 6> tiles = {
-"##########",
-"#        #",
-"#        #",
-"#        |",
-"#        #",
-"##########",
+Matrix input = {
+  {1,1,1,1,1,1,1,1,1,1,1,1},
+  {1,1,1,1,1,1,1,1,1,1,1,1},
+  {1,1,1,0,1,1,1,1,1,1,1,1},
+  {1,1,1,1,1,1,1,1,1,1,1,1},
+  {1,1,1,1,1,1,1,1,1,1,1,1},
 };
 
-
-
+Matrix walls = {
+  {1,1,1,1,1,1,1,1,1,1,1,1},
+  {1,0,0,0,0,1,1,0,0,0,0,1},
+  {1,0,0,0,0,0,0,0,0,1,0,1},
+  {1,0,0,0,0,1,1,0,0,1,0,1},
+  {1,1,1,1,1,1,1,1,1,1,1,1},
+};
 
 int main() {
   using namespace ftxui;
@@ -35,17 +43,17 @@ int main() {
 
   // A triangle following the mouse, using braille characters.
   auto map = Renderer([&] {
-    for(size_t i = 0; i < tiles.size(); ++i) {
-      c.DrawText(50, 50+i*4, tiles[i]);
-    }
+    Matrix result = dijkstra_map(input, walls, 1000);
 
-    for(size_t i = 0; i < tiles[0].size() - 2; i++) {
-      for(size_t j = 0; j < tiles.size() - 2; j++) {
-        c.DrawText(52+i*2, 54+j*4, ".", Color::Yellow);
+    for(size_t x = 0; x < result[0].size(); ++x) {
+      for(size_t y = 0; y < result.size(); ++y) {
+        auto val = result[y][x];
+        const string tile = val == 1000 ? "#" : fmt::format("{}", result[y][x]);
+        c.DrawText(22+x*2, 24+y*4, tile);
       }
     }
 
-    c.DrawText(50+3*4, 50+3*4, "@", Color::Blue);
+    c.DrawText(20+4*2, 20+3*4, "@", Color::Blue);
 
     return canvas(c);
   });

map.cpp

@@ -41,11 +41,11 @@ Matrix dijkstra_map(Matrix &input_map, Matrix &walls_map, int limit) {
 
   // Initialize the new array with every pixel at limit distance
   // NOTE: this is normally ones() * limit
+  limit = limit == 0 ? h * w : limit;
   Matrix new_arr = Matrix(h, MatrixRow(w, limit));
   Matrix closed = walls_map;
   PairList starting_pixels;
   PairList open_pixels;
-  limit = limit == 0 ? h * w : limit;
 
   // First pass: Add starting pixels and put them in closed
  for(size_t counter = 0; counter < h * w; counter++) {
@@ -64,15 +64,14 @@ Matrix dijkstra_map(Matrix &input_map, Matrix &walls_map, int limit) {
   }
 
   // Third pass: Iterate filling in the open list
-  int counter = 1;
-  while(counter < limit && !open_pixels.empty()) {
+  int counter = 1; // leave this here so it's available below
+  for(; counter < limit && !open_pixels.empty(); ++counter) {
     PairList next_open;
     for(auto sp : open_pixels) {
       new_arr[sp.j][sp.i] = counter;
       add_neighbors(next_open, closed, sp.j, sp.i);
     }
     open_pixels = next_open;
-    ++counter;
   }
 
   // Last pass: flood last pixels

tests/dijkstra.json

@@ -34,8 +34,8 @@
   "expected": [
     [1, 1, 1, 0],
      [1, 0, 1, 1],
-     [1, 0, 0, 2],
-     [1, 1, 0, 3]
+     [1, 0, 16, 2],
+     [1, 1, 16, 3]
   ],
   "limit": 0
 }]