WOOO

2019/3rdDay/challenge2.cpp

@@ -0,0 +1,116 @@
+#include <iostream>
+#include <fstream>
+#include <sstream>
+#include <string>
+#include <vector>
+#include <unordered_map>
+#include <algorithm>
+#include <math.h>
+
+std::vector<std::string> tokenise( std::string input )
+{
+    std::stringstream ssInput( input );
+    std::vector<std::string> stream;
+
+    std::string s;
+	while( std::getline( ssInput, s, ',' ) ) {
+		stream.push_back( s );
+	}
+
+    return stream;
+}
+
+struct vec2
+{
+    int x;
+    int y;
+
+    bool operator==(const vec2& v) const
+    {
+        return x == v.x && y == v.y;
+    }
+};
+
+namespace std
+{
+    template <>
+    struct hash<vec2>
+    {
+        size_t operator()( const vec2& v ) const
+        {
+            return v.x ^ v.y;
+        }
+    };
+}
+
+std::unordered_map<vec2, int> genPath( std::vector<std::string> wire )
+{
+    std::unordered_map<vec2, int> path;
+    vec2 pos = { 0, 0 };
+    path[pos] = 0;
+
+    auto up     = []( vec2& p ) { p.y -= 1; };
+	auto down   = []( vec2& p ) { p.y += 1; };
+	auto left   = []( vec2& p ) { p.x -= 1; };
+	auto right  = []( vec2& p ) { p.x += 1; };
+
+    void (*stepSingle)(vec2&);
+
+    int stepCounter = 0;
+
+    for ( auto& element : wire )
+    {
+        char dir = element[0];
+        int steps = std::stoi( element.substr( 1, element.size() ) );
+
+        switch ( dir )
+        {
+            case 'U': stepSingle = up; break;
+            case 'D': stepSingle = down; break;
+            case 'R': stepSingle = right; break;
+            case 'L': stepSingle = left; break;
+            default: break;
+        }
+
+        for( int i = 0; i < steps; i++ )
+        {
+            stepSingle( pos );
+            path[pos] = ++stepCounter;
+        }
+    }
+
+    return path;
+}
+
+int main(int argc, char** argv)
+{
+
+    std::ifstream infile( argv[1] );
+
+    std::string input;
+
+    std::getline( infile, input );
+    std::vector<std::string> wireS1 = tokenise( input );
+
+    std::getline( infile, input );
+    std::vector<std::string> wireS2 = tokenise( input );
+
+    auto path1 = genPath(wireS1);
+    auto path2 = genPath(wireS2);
+
+    int res = INFINITY;
+
+    for ( auto [pos, steps] : path2 )
+    {
+        // Intersect
+        if ( path1.count( pos ) > 0 )
+        {
+            std::cout << pos.x << ":" << pos.y << " " << steps << std::endl;
+            if ( steps == 0 ) continue;
+            res = std::min( res, path1[pos] + path2[pos] );
+        }
+    }
+
+    std::cout << "Shortest Distance to Complete : " << res << std::endl;
+
+}