Solve problems for day 1

q1.cpp

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+#include <algorithm>
+#include <fstream>
+#include <iostream>
+#include <sstream>
+#include <unordered_map>
+#include <vector>
+
+int q1(std::ifstream &in) {
+    std::vector<int> l1;
+    std::vector<int> l2;
+     
+ //   for (std::string line; std::getline(in, line);) {
+ //       std::string left = line.substr(0, line.find(" "));
+ //       std::string right = line.substr(line.rfind(" "));
+ //       l1.push_back(std::stoi(left));
+ //       l2.push_back(std::stoi(right));
+ //   }
+
+    for (std::string line; std::getline(in, line);) {
+        int left, right;
+        std::stringstream s(line);
+        s >> left >> right;
+        l1.push_back(left);
+        l2.push_back(right);
+    }
+
+    std::sort(l1.begin(), l1.end()); 
+    std::sort(l2.begin(), l2.end());
+
+    int sum = 0;
+    for (int i = 0; i < l1.size(); i++) {
+        sum += abs(l1[i]-l2[i]);
+    }
+    return sum;
+}
+
+int q2(std::ifstream &in) {
+    std::vector<int> l1;
+    std::unordered_map<int, int> l2;
+     
+    for (std::string line; std::getline(in, line);) {
+        std::string left = line.substr(0, line.find(" "));
+        std::string right = line.substr(line.rfind(" "));
+        l1.push_back(std::stoi(left));
+        l2[std::stoi(right)]++;
+    }
+
+    std::sort(l1.begin(), l1.end()); 
+
+    int sum = 0;
+    for (int i = 0; i < l1.size(); i++) {
+        sum += l1[i] * l2[l1[i]];
+    }
+    return sum;
+}
+
+int main() {
+    std::ifstream input("i1.txt");
+    std::cout << "Part 1: " << q1(input) << std::endl;
+
+    // Could re-read the file, or just seek to the beginning.
+    // input = std::ifstream("i1.txt");
+    input.clear();
+    input.seekg(0);
+    std::cout << "Part 2: " << q2(input) << std::endl;
+}

q1.py

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+from typing import Counter
+
+
+def q1(text: str):
+    l1 = []
+    l2 = []
+    for line in text.splitlines():
+        left, right = list(map(int, line.replace("   ", " ").split()))
+        l1.append(left)
+        l2.append(right)
+
+    l1.sort()
+    l2.sort()
+
+    return sum(abs(left-right) for left, right in zip(l1, l2))
+
+def q2(text: str):
+    l1 = []
+    l2 = Counter()
+    for line in text.splitlines():
+        left, right = list(map(int, line.replace("   ", " ").split()))
+        l1.append(left)
+        l2[right] += 1
+
+    return sum(left * l2[left] for left in l1)
+
+if __name__ == "__main__":
+    with open("i1.txt") as f:
+        print(q1(f.read()))
+
+    with open("i1.txt") as f:
+        print(q2(f.read()))