advent2024

commit 1ef73fadbacf267c38ca06b63edab52da8bb4366
parent 485d0c28244aa1471467502a579ccf939b972dbe
Author: bsandro <email@bsandro.tech>
Date:   Wed, 11 Dec 2024 23:14:05 +0200

Day 11 p1

Diffstat:
A
day11/Makefile
 | 
28
++++++++++++++++++++++++++++
A
day11/input.txt
 | 
1
+
A
day11/main.cpp
 | 
91
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
A
day11/test1.txt
 | 
1
+
A
day11/test2.txt
 | 
1
+

5 files changed, 122 insertions(+), 0 deletions(-)
diff --git a/day11/Makefile b/day11/Makefile
@@ -0,0 +1,28 @@
+NAME=$(shell basename ${PWD})
+SRC=$(wildcard *.cpp)
+DEPS:=$(wildcard *.hpp)
+OBJ:=$(SRC:.cpp=.o)
+CXXFLAGS=-O2 -std=c++23 -Werror -Wall -Wextra -I. -I../include
+LDFLAGS=-lstdc++
+
+all: $(NAME)
+
+.PHONY: clean run
+
+clean:
+	rm -f $(OBJ) $(NAME)
+
+%.o : %.c $(DEPS)
+	@$(CC) $(CFLAGS) -c $< -o $@
+
+$(NAME): $(OBJ)
+	@$(CC) $(OBJ) -o $@ $(LDFLAGS)
+
+run: $(NAME)
+	@./$(NAME) input.txt
+
+test1: $(NAME)
+	@./$(NAME) test1.txt
+
+test2: $(NAME)
+	@./$(NAME) test2.txt
diff --git a/day11/input.txt b/day11/input.txt
@@ -0,0 +1 @@
+1 24596 0 740994 60 803 8918 9405859
diff --git a/day11/main.cpp b/day11/main.cpp
@@ -0,0 +1,91 @@
+#include <iostream>
+#include <filesystem>
+#include <fstream>
+#include <vector>
+#include <cstring>
+#include <cstdio>
+#include <tuple>
+#include <algorithm>
+#include <thread>
+#include <future>
+#include "utils.hpp"
+
+typedef std::vector<uint64_t> Data;
+
+template<typename T>
+T read_file(const std::string &path) {
+    std::ifstream ifs(path, std::ios::binary);
+    if (!ifs.is_open()) {
+        throw std::runtime_error(path+":"+std::strerror(errno));
+    }
+    T buf;
+    for (std::string str; std::getline(ifs, str, ' ');) {
+        if (!str.empty()) buf.push_back(std::stoi(str));
+    }
+    return buf;
+}
+
+void blink(Data &stones) {
+    for (auto it=stones.begin(); it!=stones.end(); ++it) {
+        std::string s = std::to_string(*it);
+        if (*it==0) {
+            *it = 1;
+        } else if (s.size()%2==0) {
+            uint64_t n1 = std::stoi(s.substr(0, s.size()/2));
+            uint64_t n2 = std::stoi(s.substr(s.size()/2, s.size()));
+            *it = n2;
+            it = stones.insert(it, n1);
+            it++;
+        } else {
+            *it *= 2024;
+        }
+    }
+}
+
+void blink2(uint64_t start, int num, std::promise<uint64_t> &&result) {
+    Data stones;
+    stones.push_back(start);
+    for (int i=0; i<num; ++i) {
+        blink(stones);
+    }
+    result.set_value(stones.size());
+}
+
+void printStones(const Data &stones) {
+    for (auto n:stones) {
+        std::cout << "[" << n << "]";
+    }
+    std::cout << std::endl;
+}
+
+int64_t part1(Data input [[ maybe_unused ]]) {
+    uint64_t sum = 0;
+    std::vector<std::pair<std::jthread, std::future<uint64_t>>> workers;
+    for (uint64_t num:input) {
+        std::pair<std::jthread, std::future<uint64_t>> p;
+        std::promise<uint64_t> pr;
+        p.second = pr.get_future();
+        p.first = std::jthread(blink2, num, 25, std::move(pr));
+        workers.push_back(std::move(p));
+    }
+    for (auto &p:workers) {
+        p.first.join();
+        sum += p.second.get();
+    }
+    return sum;
+}
+
+int64_t part2(Data input [[ maybe_unused ]]) {
+    return 0;
+}
+
+int main(int argc, char **argv) {
+    Performance perf;
+    const std::string fname = argc>1 ? argv[1] : "test1.txt";
+    std::cout << "AoC 2024 day 11 " << fname << std::endl;
+    Data input = read_file<Data>(fname);
+    std::cout << "part1: " << part1(input) << std::endl;
+    std::cout << "part2: " << part2(input) << std::endl;
+
+    return 0;
+}
diff --git a/day11/test1.txt b/day11/test1.txt
@@ -0,0 +1 @@
+0 1 10 99 999
diff --git a/day11/test2.txt b/day11/test2.txt
@@ -0,0 +1 @@
+125 17