day 2

2020/2.cpp

@@ -0,0 +1,79 @@
+#include <iostream>
+#include <fstream>
+#include <sstream>
+#include <vector>
+
+std::vector<std::string> split(const std::string& str, const std::string& delim)
+{
+    std::vector<std::string> tokens;
+    size_t prev = 0, pos = 0;
+    do
+    {
+        pos = str.find(delim, prev);
+        if (pos == std::string::npos) pos = str.length();
+        std::string token = str.substr(prev, pos-prev);
+        if (!token.empty()) tokens.push_back(token);
+        prev = pos + delim.length();
+    }
+    while (pos < str.length() && prev < str.length());
+    return tokens;
+}
+
+std::vector<std::string> readFile(std::string path)
+{
+    std::ifstream file(path);
+    std::vector<std::string> input;
+    std::string line;
+    
+    while(std::getline(file, line))
+    {
+        input.push_back(line);
+    }
+    return input;
+}
+
+
+int main()
+{
+    std::vector<std::string> input = readFile("./2.txt");
+
+    int total = 0;
+    for (auto& line : input)
+    {
+        std::vector<std::string> parts = split(line, " ");
+
+        int lower, upper;
+        std::vector<std::string> bounds = split(parts[0], "-");
+        lower = std::stoi(bounds[0]);
+        upper = std::stoi(bounds[1]);
+
+        char searchterm = parts[1][0];
+
+        int count = 0;
+        for (int i = 0; i < parts[2].length(); i++)
+            if (parts[2][i] == searchterm) count++;
+
+        if (count >= lower && count <= upper) total++;
+    }
+
+    std::cout << "Part 1, valid passwords: " << total << std::endl;
+
+    total = 0;
+    for (auto& line : input)
+    {
+        std::vector<std::string> parts = split(line, " ");
+
+        int first, second;
+        std::vector<std::string> bounds = split(parts[0], "-");
+        first = std::stoi(bounds[0]) - 1;
+        second = std::stoi(bounds[1]) - 1;
+
+        char searchterm = parts[1][0];
+
+        // A terrible logical XOR
+        if (!(parts[2][first] == searchterm) != !(parts[2][second] == searchterm)) total++;
+    }
+
+    std::cout << "Part 2, valid passwords: " << total << std::endl;
+
+}