From 778583267377f25081a64bd8b16304a8e06fd57a Mon Sep 17 00:00:00 2001
From: Avril <flanchan@cumallover.me>
Date: Wed, 9 Dec 2020 12:35:30 +0000
Subject: [PATCH] day9: part1

---
 day9/Makefile | 41 +++++++++++++++++++++++
 day9/day9.c   | 92 ++++++++++++++++++++++++++++++++++++++++++++++++++
 day9/map.c    | 93 +++++++++++++++++++++++++++++++++++++++++++++++++++
 day9/map.h    | 28 ++++++++++++++++
 4 files changed, 254 insertions(+)
 create mode 100644 day9/Makefile
 create mode 100644 day9/day9.c
 create mode 100644 day9/map.c
 create mode 100644 day9/map.h

diff --git a/day9/Makefile b/day9/Makefile
new file mode 100644
index 0000000..d21ba00
--- /dev/null
+++ b/day9/Makefile
@@ -0,0 +1,41 @@
+SRC:= day9.c map.c
+
+OPT_FLAGS?= -march=native -flto \
+	 -march=native -fgraphite -fopenmp -floop-parallelize-all -ftree-parallelize-loops=4 \
+	 -floop-interchange -ftree-loop-distribution -floop-strip-mine -floop-block \
+	 -fno-stack-check -fno-strict-aliasing 
+
+COMMON_FLAGS?=-pipe -O3 -Wall -pedantic -Wextra -Wstrict-aliasing
+
+C_OPT_FLAGS=$(OPT_FLAGS)
+CXX_OPT_FLAGS=$(OPT_FLAGS) -felide-constructors -fno-exceptions
+LD_OPT_FLAGS?=-O3 -flto
+
+INCLUDE=../common/include
+
+CFLAGS?=$(COMMON_FLAGS) $(C_OPT_FLAGS) --std=gnu11
+CXXFLAGS?=$(COMMON_FLAGS) $(CXX_OPT_FLAGS) --std=gnu++20
+LDFLAGS?=$(LD_OPT_FLAGS)
+
+CFLAGS+=-I$(INCLUDE)
+
+.PHONY: all
+all: part1 part2
+
+inpu%.h: inpu%
+	@rm -f $@
+	while read line; do \
+		echo "$$line," >> $@; \
+	done < $<
+	
+part1: $(SRC) | input.h
+	$(CC) $(SRC) $(CFLAGS) -o $@ $(LDFLAGS)
+	strip $@
+
+part1-test: $(SRC) | input-test.h
+	$(CC) $(SRC) -DTEST $(CFLAGS) -o $@ $(LDFLAGS)
+	strip $@
+
+clean:
+	rm -f part{1,2}{,-test}
+	rm -f input{,-test}.h
diff --git a/day9/day9.c b/day9/day9.c
new file mode 100644
index 0000000..0d7c837
--- /dev/null
+++ b/day9/day9.c
@@ -0,0 +1,92 @@
+#include <stdint.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+
+#include "map.h"
+
+typedef uint64_t u64;
+
+#ifdef TEST
+#define PREAMBLE 5
+#else
+#define PREAMBLE 25
+#endif
+
+#define input_sz (sizeof(input) / sizeof(u64))
+const u64 input[] = {
+#ifdef TEST
+#include "input-test.h"
+#else
+#include "input.h"
+#endif
+};
+
+#define box(t) (calloc(sizeof(t), 1))
+
+struct pair {
+	bool valid;
+	u64 num;
+	u64 sum[2];
+};
+
+inline static void insert_page(map_t* restrict where, u64 key, size_t i)
+{
+	//if(key > PAGE_SIZE) panic("Data too large, increase page size to fit %lu in a single page", key);
+	map_insert(where, key, i);
+}
+
+static void calculate_deficits(const u64 pre[static PREAMBLE], map_t * restrict output, u64 target)
+{
+	for(size_t i=0;i<PREAMBLE;i++)
+		if(target > pre[i])
+			insert_page(output, target - pre[i], i);
+}
+
+#ifdef PART2
+static u64 find_set(u64 target)
+{
+	
+}
+#endif
+
+int main()
+{
+	map_t def = map_new();
+	struct pair result[input_sz] = {0};
+	
+	for(register size_t i= PREAMBLE;i<input_sz;i++)
+	{
+		calculate_deficits(&input[i-PREAMBLE], &def, input[i]);
+		
+		for(register size_t j=0;j<PREAMBLE;j++)
+		{
+			result[i].num = input[i];
+
+			size_t idx;
+			u64 us = 	  input[(i-PREAMBLE)+j];
+			if(!map_get(&def, us, &idx)) continue;
+			u64 other = 	  input[(i-PREAMBLE)+idx];
+
+			// Found pair!
+			result[i] = (struct pair){.valid = other!=us, .num=input[i], .sum = { us, other }};
+		}
+		map_clear(&def);
+	}
+	map_free(def);
+
+	for(register size_t i=PREAMBLE;i<input_sz;i++)
+	{
+		if(!result[i].valid && !(result[i].sum[0] | result[i].sum[1])) {
+#ifdef PART2
+			return find_set(result[i].num);
+#else
+			printf("%lu\n", result[i].num);
+			return 0;
+#endif
+		}
+	}
+	fprintf(stderr, "Not found\n");
+	return 1;
+}
diff --git a/day9/map.c b/day9/map.c
new file mode 100644
index 0000000..4674858
--- /dev/null
+++ b/day9/map.c
@@ -0,0 +1,93 @@
+#include <stdbool.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "map.h"
+
+#define box(t) calloc(sizeof(t), 1)
+
+struct page {
+	struct entry {
+		bool set;
+		map_key_t key;
+		map_value_t value;
+	} p[PAGE_SIZE];
+
+	struct page* next;
+};
+
+map_t map_new()
+{
+	register map_t rval;
+
+	rval.page0 = box(struct page);
+	return rval;
+}
+
+static inline size_t page_index(map_key_t k)
+{
+	return (size_t)(k % PAGE_SIZE);
+}
+
+void map_insert(map_t * restrict into, map_key_t k, map_value_t v)
+{
+	struct page** p = &into->page0;
+	size_t i = page_index(k);
+
+	while(*p) {
+		register struct page* page = *p;
+		if (!page->p[i].set || page->p[i].key == k)
+		{
+			page->p[i] = (struct entry){.set = true, .key = k, .value = v};
+			return;
+		}
+		p = &page->next;
+	}
+	// p == &<last page>.next == &NULL
+	(*p = box(struct page))->p[i] = (struct entry){.set = true, .key = k, .value = v};
+}
+
+bool map_get(const map_t* from, map_key_t k, map_value_t* restrict v)
+{
+	const struct page* p = from->page0;
+	size_t i = page_index(k);
+
+	while(p) {
+		if (p->p[i].set && p->p[i].key ==k) {
+			*v =  p->p[i].value;
+			return true;
+		}
+		p = p->next;
+	}
+	return false;
+}
+
+void map_free(map_t map)
+{
+	while(map.page0)
+	{
+		struct page* next = map.page0->next;
+		free(map.page0);
+		map.page0 = next;
+	}
+}
+
+static void _map_walk(map_t* restrict map, void (*cb)(struct page* page))
+{
+	struct page* page=  map->page0;
+	while(page)
+	{
+		cb(page);
+		page = page->next;
+	}
+}
+
+static void _map_page_clear(struct page* page)
+{
+	memset(page, 0, sizeof(struct page));
+}
+
+void map_clear(map_t* restrict map)
+{
+	_map_walk(map, &_map_page_clear);
+}
diff --git a/day9/map.h b/day9/map.h
new file mode 100644
index 0000000..7b14c36
--- /dev/null
+++ b/day9/map.h
@@ -0,0 +1,28 @@
+#ifndef _MAP_H
+#define _MAP_H
+
+#ifndef KELEMENT
+#include <stdint.h>
+#	define KELEMENT uint64_t
+#endif
+#ifndef VELEMENT
+#include <stddef.h>
+#	define VELEMENT size_t
+#endif
+
+typedef KELEMENT map_key_t;
+typedef VELEMENT map_value_t;
+
+#define PAGE_SIZE UINT16_MAX
+
+typedef struct _map {
+	struct page* page0;
+} map_t;
+
+map_t map_new();
+void map_insert(map_t * restrict into, map_key_t k, map_value_t v);
+bool map_get(const map_t* from, map_key_t k, map_value_t* restrict v);
+void map_free(map_t map);
+void map_clear(map_t* restrict map);
+
+#endif /* _MAP_H */