Add day 1

Makefile

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+CXXFLAGS := -std=c++17 -O2 -Wall -Wextra

d01.cc

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+#include <iostream>
+#include <fstream>
+#include <vector>
+using namespace std;
+
+int main(int argc, char *argv[]) {
+    if (argc <= 1) return 1;
+    ifstream input(argv[1]);
+
+    vector<unsigned> numbers;
+    unsigned num;
+    while (input >> num) {
+        numbers.push_back(num);
+    }
+
+    unsigned part1 = 0;
+    for (size_t i = 1; i < numbers.size(); i++) {
+        if (numbers[i] > numbers[i-1]) part1++;
+    }
+    cout << part1 << endl;
+
+    unsigned part2 = 0;
+    for (size_t i = 4; i < numbers.size(); i++) {
+        unsigned win1 = numbers[i-1] + numbers[i-2] + numbers[i-3];
+        unsigned win2 = numbers[i]   + numbers[i-1] + numbers[i-2];
+        if (win2 > win1) part2++;
+    }
+    cout << part2 << endl;
+}

d01_output.txt

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+1301
+1346