Day 5

d5/main.cxx

@@ -0,0 +1,87 @@
+#include <iostream>
+#include <algorithm>
+#include <numeric>
+#include <fstream>
+#include <sstream>
+#include <string>
+#include <vector>
+#include <limits>
+#include <omp.h>
+
+struct MapRow
+{
+  long source;
+  long destination;
+  long range;
+};
+
+long findDestination(long seed, const std::vector<std::vector<MapRow>> &maps)
+{
+  long location{seed};
+  for (const auto &map : maps)
+  {
+    for (const auto &mr : map)
+    {
+      if (location >= mr.source && location < mr.source + mr.range)
+      {
+        location = mr.destination + (location - mr.source);
+        break;
+      }
+    }
+  }
+  return location;
+}
+
+int main()
+{
+  std::ifstream file{"../d5/input.txt"};
+  std::string line, ignored;
+  std::vector<std::pair<long, long>> seeds;
+  std::vector<std::vector<MapRow>> maps{};
+  long mapIndex{-1};
+
+  std::getline(file, line);
+  std::stringstream seedSS(line);
+  seedSS >> ignored;
+  while (seedSS.tellg() != -1)
+  {
+    long seedStart, seedRange;
+    seedSS >> seedStart >> seedRange;
+    seeds.emplace_back(seedStart, seedRange);
+  }
+
+  while (std::getline(file, line))
+  {
+    std::stringstream iss(line);
+
+    if (isalpha(line[0]))
+    {
+      mapIndex += isalpha(line[0]);
+      maps.push_back({});
+    }
+
+    while (isdigit(line[0]) && iss.tellg() != -1)
+    {
+      MapRow mr;
+      iss >> mr.destination >> mr.source >> mr.range;
+      maps[mapIndex].emplace_back(mr);
+    }
+  }
+
+  long result = std::numeric_limits<long>::max();
+  int i, j;
+
+#pragma omp parallel for schedule(static) private(i, j) shared(seeds, result, maps)
+  for (i = 0; i < seeds.size(); i++)
+  {
+    for (j = 0; j < seeds[i].second; j++)
+    {
+      long destination = findDestination(seeds[i].first + j, maps);
+      result = std::min(result, destination);
+    }
+  }
+
+  std::cout << result << std::endl;
+
+  return 0;
+}