89 lines
2.3 KiB
D
89 lines
2.3 KiB
D
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module day3.part1;
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import std.file;
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import std.stdio;
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import std.bitmanip;
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void writeBinary(uint n) {
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for (int i = 31; i >= 0; i--) {
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uint b = (n & (1 << i)) > 0 ? 1 : 0;
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writef("%d ", b);
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}
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writeln();
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}
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void binaryDiagnostic() {
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auto f = File("source/day3/input.txt", "r");
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int[ubyte] frequencies;
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int count = 0;
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foreach (line; f.byLine) {
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count++;
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ubyte idx = 0;
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foreach (c; line) {
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if (idx !in frequencies) frequencies[idx] = 0;
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if (c == '1') frequencies[idx]++;
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idx++;
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}
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}
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ulong bitCount = frequencies.length;
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uint gamma = 0;
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uint epsilon = 0;
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foreach (idx, freq; frequencies) {
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if (freq > count / 2) {
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gamma |= (1 << (bitCount - 1 - idx));
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} else {
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epsilon |= (1 << (bitCount - 1 - idx));
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}
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}
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writefln("Gamma: %d, Epsilon: %d, Power: %d", gamma, epsilon, gamma * epsilon);
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}
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bool is1Common(uint[] values, int idx, int bitCount, bool type) pure {
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int count = 0;
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foreach (v; values) {
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if ((v & (1 << (bitCount - 1 - idx))) > 0) count++;
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}
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if (type) {
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return count >= (values.length - count);
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} else {
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return count < (values.length - count);
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}
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}
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void filter(ref uint[] values, int idx, int bitCount, bool type) pure {
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bool common = is1Common(values, idx, bitCount, type);
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uint[] newValues = [];
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foreach (v; values) {
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bool b = (v & (1 << (bitCount - 1 - idx))) > 0;
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if (b == common) newValues ~= v;
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}
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values = newValues;
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}
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uint findValue(uint[] values, int bitCount, bool type) {
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int idx = 0;
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while (values.length > 1) {
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filter(values, idx++, bitCount, type);
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}
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return values[0];
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}
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void binaryDiagnostic2() {
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auto f = File("source/day3/input.txt", "r");
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uint[] values = [];
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int bitCount = 0;
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foreach (line; f.byLine) {
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bitCount = cast(int) line.length;
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int idx = 0;
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uint value = 0;
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foreach (c; line) {
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if (c == '1') value |= (1 << line.length - 1 - idx);
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idx++;
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}
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values ~= value;
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}
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uint o2 = findValue(values, bitCount, true);
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uint co2 = findValue(values, bitCount, false);
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writefln("Oxygen: %d, CO2: %d, LS Rating: %d", o2, co2, o2 * co2);
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}
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