98 lines
2.1 KiB
C++
98 lines
2.1 KiB
C++
#include <fstream>
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#include <iostream>
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using namespace std;
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// parses a number with up to 3 digits
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bool parseNumber(ifstream &input, int &x, char delim) {
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char c1;
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char c2;
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char c3;
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input >> c1;
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if (c1 < '0' || c1 > '9') return false;
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x = c1 - 48;
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if (input.peek() == delim) return true;
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input >> c2;
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if (c2 < '0' || c2 > '9') return false;
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x *= 10;
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x += c2 - 48;
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if (input.peek() == delim) return true;
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input >> c3;
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if (c3 < '0' || c3 > '9') return false;
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x *= 10;
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x += c3 - 48;
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return true;
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}
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bool peekCheck (ifstream &input, char c) {
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char x;
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if (input.peek() == c) {
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input >> x;
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return true;
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}
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return false;
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}
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int day2(const char *path, bool extra = true) {
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ifstream input(path);
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int result = 0;
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char c;
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bool enable = true;
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while (input >> c) {
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if (extra) {
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if (c == 'd') {
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if (!peekCheck(input, 'o')) continue;
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if (peekCheck(input, '(') && peekCheck(input, ')')) {
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enable = true;
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continue;
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}
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if (!peekCheck(input, 'n')) continue;
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if (!peekCheck(input, '\'')) continue;
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if (!peekCheck(input, 't')) continue;
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if (!peekCheck(input, '(')) continue;
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if (!peekCheck(input, ')')) continue;
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enable = false;
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}
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}
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if (c == 'm') {
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if (!peekCheck(input, 'u')) continue;
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if (!peekCheck(input, 'l')) continue;
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if (!peekCheck(input, '(')) continue;
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int x;
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parseNumber(input, x, ',');
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if (!peekCheck(input, ',')) continue;
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int y;
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parseNumber(input, y, ')');
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if (!peekCheck(input, ')')) continue;
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if (enable) result += x * y;
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}
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}
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return result;
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}
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int main(int argc, char *argv[]) {
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int result = day2("example", false);
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cout << "example (without do)" << endl << result << endl;
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result = day2("example", true);
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cout << "example (with do)" << endl << result << endl;
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result = day2("input", false);
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cout << "input (without do)" << endl << result << endl;
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result = day2("input", true);
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cout << "input (without do)" << endl << result << endl;
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return 0;
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}
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