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Partial implementation for part 2.

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Bert Peters
2019-12-03 18:04:34 +01:00
parent a1d871fd17
commit a40da965f0
6 changed files with 28 additions and 8 deletions
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30
2019/src/day03.cpp
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@@ -2,7 +2,6 @@
#include <charconv>
#include <iostream>
#include <limits>
#include <unordered_set>
#include <unordered_map>
#include <utility>
#include <vector>
@@ -20,10 +19,11 @@ namespace {
{'R', {1, 0}},
};
std::unordered_set<point_t> get_points(std::string_view line) {
std::unordered_set<point_t> points{};
std::unordered_map<point_t, int> get_points(std::string_view line) {
std::unordered_map<point_t, int> points{};
point_t pos = {};
int steps = 0;
for (auto entry = aoc2019::strtok(line); !line.empty() || !entry.empty(); entry = aoc2019::strtok(line)) {
const auto dir = DIRECTION_MAP.at(entry[0]);
std::size_t amount = 0;
@@ -32,14 +32,16 @@ namespace {
for (std::size_t i = 0; i < amount; ++i) {
pos += dir;
points.insert(pos);
if (!points.count(pos)) {
points[pos] = ++steps;
}
}
}
return points;
}
std::pair<std::unordered_set<point_t>, std::unordered_set<point_t>> read_input(std::istream& input) {
std::pair<std::unordered_map<point_t, int>, std::unordered_map<point_t, int>> read_input(std::istream& input) {
std::string buffer;
std::getline(input, buffer);
auto a = get_points(buffer);
@@ -56,8 +58,8 @@ void aoc2019::day03_part1(std::istream &input, std::ostream &output) {
int best = std::numeric_limits<int>::max();
for (const auto& point : a) {
if (b.count(point) && point.l1() < best) {
best = point.l1();
if (b.count(point.first) && point.first.l1() < best) {
best = point.first.l1();
}
}
@@ -65,5 +67,17 @@ void aoc2019::day03_part1(std::istream &input, std::ostream &output) {
}
void aoc2019::day03_part2(std::istream &input, std::ostream &output) {
output << "Not implemented\n";
auto [a, b] = read_input(input);
int best = std::numeric_limits<int>::max();
for (const auto& ap : a) {
const auto bp = b.find(ap.first);
if (bp != b.cend() && (ap.second + bp->second) < best) {
best = ap.second + bp->second;
}
}
output << best << std::endl;
}