2024 day 18

README.md

@@ -376,6 +376,8 @@
   * [Day 16](year2024/day16) - Reindeer Maze
 
   * [Day 17](year2024/day17) - Chronospatial Computer :star:
+
+  * [Day 18](year2024/day18) - RAM Run :star:  
 </details>
 
 Legend

year2024/CMakeLists.txt

@@ -19,3 +19,4 @@ add_subdirectory(day14)
 add_subdirectory(day15)
 add_subdirectory(day16)
 add_subdirectory(day17)
+add_subdirectory(day18)

year2024/day18/CMakeLists.txt

@@ -0,0 +1,16 @@
+cmake_minimum_required(VERSION 3.29)
+
+set(DAY 18)
+
+project("${YEAR} Day ${DAY}" LANGUAGES CXX)
+
+add_compile_definitions(DAY=day_${DAY})
+add_compile_definitions(YEAR=year_${YEAR})
+
+include_directories(..)
+include_directories(../..)
+
+set(CMAKE_CXX_STANDARD 20)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+
+add_executable(${YEAR}_day_${DAY} ../../main.cpp ../../aoc.cpp day_${DAY}.cpp input)

year2024/day18/day_18.cpp

@@ -0,0 +1,166 @@
+#include "day"
+
+//---------------------------------------------------------------------------//
+namespace aoc::YEAR::DAY {
+
+//---------------------------------------------------------------------------//
+// Test data
+std::string testinput (
+R"(5,4
+4,2
+4,5
+3,0
+2,1
+6,3
+2,4
+1,5
+0,6
+3,3
+2,6
+5,1
+1,2
+5,5
+2,5
+6,5
+1,4
+0,4
+6,4
+1,1
+6,1
+1,0
+0,5
+1,6
+2,0
+)");
+
+//---------------------------------------------------------------------------//
+struct P{
+    int x,y;
+};
+
+//---------------------------------------------------------------------------//
+inline ::std::istream& test_input() {
+    static std::stringstream ss;
+    return ss = std::stringstream ( testinput );;
+}
+
+::std::vector<::std::string> load ( ::std::istream& fs ) {
+    ::std::string line;
+    ::std::vector<::std::string> ret;
+    while ( !fs.eof() ) {
+        std::getline ( fs, line );
+        if( !line.empty() )
+            ret.push_back ( line );
+    }
+    return ret;
+}
+
+//---------------------------------------------------------------------------//
+void Task_1 ( ::std::istream& puzzle_input ) {
+    auto ans = 0ull;
+    std::vector<int> maze;
+
+    //aoc::test_enable();
+
+    auto& file = aoc::is_test_enabled() ? test_input() : puzzle_input;
+    auto data = load ( file );
+    constexpr int W=71;
+
+    maze.resize ( W*W, INT32_MAX );
+
+    for ( int i=0; i<1024; i++ ) {
+        std::istringstream is{data[i]};
+        int x,y;
+        char c;
+        is >> x >> c>> y;
+        maze[x+y*W]=-1;
+    }
+
+    std::vector<P> l { P { 0, 0 } };
+    maze [ 0 ] = 0;
+    while ( !l.empty() ) {
+        auto p = l.back(); l.pop_back();
+        if ( p.x+1 < W && maze[p.x+p.y*W]+1 < maze[p.x+p.y*W+1] ) {
+            maze[p.x+p.y*W+1] = maze[p.x+p.y*W]+1;
+            l.push_back ( P { p.x+1, p.y } );
+        }
+        if ( p.x-1 >=0 && maze[p.x+p.y*W]+1 < maze[p.x+p.y*W-1] ) {
+            maze[p.x+p.y*W-1] = maze[p.x+p.y*W]+1;
+            l.push_back ( P { p.x-1, p.y } );
+        }
+        if ( p.y+1 < W && maze[p.x+p.y*W]+1 < maze[p.x+(p.y+1)*W] ) {
+            maze[p.x+(p.y+1)*W] = maze[p.x+p.y*W]+1;
+            l.push_back ( P { p.x, p.y+1 } );
+        }
+        if ( p.y-1 >=0 && maze[p.x+p.y*W]+1 < maze[p.x+(p.y-1)*W] ) {
+            maze[p.x+(p.y-1)*W] = maze[p.x+p.y*W]+1;
+            l.push_back ( P { p.x, p.y-1 } );
+        }
+    }
+    ans = maze[W*W-1];
+
+    OUT ( ans );
+}
+
+
+//---------------------------------------------------------------------------//
+void Task_2 ( ::std::istream& puzzle_input ) {
+    ::std::string ans;
+    //aoc::test_enable();
+
+    auto& file = aoc::is_test_enabled() ? test_input() : puzzle_input;
+    auto data = load ( file );
+    std::vector<int> maze;
+    constexpr int W=71;
+    maze.resize ( W*W, INT32_MAX );
+
+    int i = 0;
+    int x = 0, y = 0;
+    for ( ; i < 1024; i++ ) {
+        std::istringstream is{data[i]};
+        char c;
+        is >> x >> c>> y;
+        maze [ x + y * W ] = -1;
+    }
+
+    int len = 0;
+    while ( len != INT32_MAX && i < data.size() ) {
+        std::vector<P> l { P { 0, 0 } };
+        maze [ 0 ] = 0;
+        for ( int i = 1; i < W*W; i++ ) if ( maze[i]!=-1 ) maze[i] = INT32_MAX;
+        while ( !l.empty() ) {
+            auto p = l.back(); l.pop_back();
+            if ( p.x+1 < W && maze[p.x+p.y*W]+1 < maze[p.x+p.y*W+1] ) {
+                maze[p.x+p.y*W+1] = maze[p.x+p.y*W]+1;
+                l.push_back ( P { p.x+1, p.y } );
+            }
+            if ( p.x-1 >= 0 && maze[p.x+p.y*W]+1 < maze[p.x+p.y*W-1] ) {
+                maze[p.x+p.y*W-1] = maze[p.x+p.y*W]+1;
+                l.push_back ( P { p.x-1, p.y } );
+            }
+            if ( p.y+1 < W && maze[p.x+p.y*W]+1 < maze[p.x+(p.y+1)*W] ) {
+                maze[p.x+(p.y+1)*W] = maze[p.x+p.y*W]+1;
+                l.push_back ( P { p.x, p.y+1 } );
+            }
+            if ( p.y-1 >= 0 && maze[p.x+p.y*W]+1 < maze[p.x+(p.y-1)*W] ) {
+                maze[p.x+(p.y-1)*W] = maze[p.x+p.y*W]+1;
+                l.push_back ( P { p.x, p.y - 1 } );
+            }
+        }
+        len = maze [ W * W - 1 ];
+        if ( len == INT32_MAX )
+            ans = std::to_string ( x ) + ',' + std::to_string ( y );
+
+        std::istringstream is { data[i++] };
+        char c;
+        is >> x >> c >> y;
+        maze [ x + y * W ] = -1;
+    }
+
+    OUT ( ans );
+}
+
+//---------------------------------------------------------------------------//
+
+}
+//---------------------------------------------------------------------------//