2019 day 3 + add br.h for some useful stuff (min, max... macros)

2019/day03/EXAMPLE.txt

@@ -1,2 +1,2 @@
-R75,D30,R83,U83,L12,D49,R71,U7,L72
+R8,U5,L5,D3
-U62,R66,U55,R34,D71,R55,D58,R83
+U7,R6,D4,L4

2019/day03/EXAMPLE2.txt

@@ -1,2 +1,2 @@
-R98,U47,R26,D63,R33,U87,L62,D20,R33,U53,R51
+R75,D30,R83,U83,L12,D49,R71,U7,L72
-U98,R91,D20,R16,D67,R40,U7,R15,U6,R7
+U62,R66,U55,R34,D71,R55,D58,R83

2019/day03/EXAMPLE3.txt

@@ -0,0 +1,2 @@
+R98,U47,R26,D63,R33,U87,L62,D20,R33,U53,R51
+U98,R91,D20,R16,D67,R40,U7,R15,U6,R7

2019/day03/Makefile

@@ -40,6 +40,10 @@ CFLAGS  += -Wno-unused-result
 CFLAGS  += -DDEBUG_DEBUG 	# activate general debug (debug.c)
 CFLAGS  += -DDEBUG_POOL		# memory pools management
 
+VALGRIND := valgrind
+VALGRINDFLAGS := -q -s --leak-check=full --show-leak-kinds=all --track-origins=yes
+
+
 TIME    := \time -f "\ttime: %E real, %U user, %S sys\n\tcontext-switch:\t%c+%w, page-faults: %F+%R\n"
 export PATH := .:$(PATH)
 
@@ -49,11 +53,12 @@ all: ex1 ex2
 
 memcheck: memcheck1
 
-memcheck1:
+memcheck1: aoc-c
-	@valgrind -q -s --track-origins=yes aoc-c -p 1 < $(INPUT)
+	@$(VALGRIND) $(VALGRINDFLAGS) aoc-c -p 1 < $(INPUT)
 
-memcheck2:
+memcheck2: aoc-c
-	@valgrind -q -s --track-origins=yes aoc-c -p 2 < $(INPUT)
+	@$(VALGRIND) $(VALGRINDFLAGS) aoc-c -p 2 < $(INPUT)
+	@#@valgrind -s --track-origins=yes aoc-c -p 2 < $(INPUT)
 
 compile: aoc-c
 
@@ -72,6 +77,11 @@ clean:
 	@echo compiling $<
 	@$(CC) $(CFLAGS) $(LDFLAGS) -I $(INCDIR) $< $(LDLIB) -o $@
 
-.c.s:
+# generate pre-processed file (.i) and assembler (.s)
+%.i: %.c
+	@echo generating $@
+	@$(CC) -E $(CFLAGS) -I $(INCDIR) $< -o $@
+
+%.s: %.c
 	@echo generating $@
 	@$(CC) -S -fverbose-asm $(CFLAGS) -I $(INCDIR) $< -o $@

2019/day03/README.org

@@ -55,12 +55,61 @@ is closer to the central port: its distance is =3 + 3 = 6=.
 
 Here are a few more examples:
 
-- =R75,D30,R83,U83,L12,D49,R71,U7,L72=
+- =R75,D30,R83,U83,L12,D49,R71,U7,L72U62,R66,U55,R34,D71,R55,D58,R83= =
-  =U62,R66,U55,R34,D71,R55,D58,R83= =distance =159=
+  distance =159=
-- =R98,U47,R26,D63,R33,U87,L62,D20,R33,U53,R51=
+- =R98,U47,R26,D63,R33,U87,L62,D20,R33,U53,R51U98,R91,D20,R16,D67,R40,U7,R15,U6,R7=
-  =U98,R91,D20,R16,D67,R40,U7,R15,U6,R7=   =distance =135=
+  = distance =135=
 
 /What is the Manhattan distance/ from the central port to the closest
 intersection?
 
-To begin, [[file:3/input][get your puzzle input]].
+Your puzzle answer was =860=.
+
+** --- Part Two ---
+It turns out that this circuit is very timing-sensitive; you actually
+need to /minimize the signal delay/.
+
+To do this, calculate the /number of steps/ each wire takes to reach
+each intersection; choose the intersection where the /sum of both wires'
+steps/ is lowest. If a wire visits a position on the grid multiple
+times, use the steps value from the /first/ time it visits that position
+when calculating the total value of a specific intersection.
+
+The number of steps a wire takes is the total number of grid squares the
+wire has entered to get to that location, including the intersection
+being considered. Again consider the example from above:
+
+#+BEGIN_EXAMPLE
+  ...........
+  .+-----+...
+  .|.....|...
+  .|..+--X-+.
+  .|..|..|.|.
+  .|.-X--+.|.
+  .|..|....|.
+  .|.......|.
+  .o-------+.
+  ...........
+#+END_EXAMPLE
+
+In the above example, the intersection closest to the central port is
+reached after =8+5+5+2 = 20= steps by the first wire and =7+6+4+3 = 20=
+steps by the second wire for a total of =20+20 = 40= steps.
+
+However, the top-right intersection is better: the first wire takes only
+=8+5+2 = 15= and the second wire takes only =7+6+2 = 15=, a total of
+=15+15 = 30= steps.
+
+Here are the best steps for the extra examples from above:
+
+- =R75,D30,R83,U83,L12,D49,R71,U7,L72U62,R66,U55,R34,D71,R55,D58,R83= =
+  =610= steps
+- =R98,U47,R26,D63,R33,U87,L62,D20,R33,U53,R51U98,R91,D20,R16,D67,R40,U7,R15,U6,R7=
+  = =410= steps
+
+/What is the fewest combined steps the wires must take to reach an
+intersection?/
+
+Your puzzle answer was =9238=.
+
+Both parts of this puzzle are complete! They provide two gold stars: **

2019/day03/aoc-c.c

@@ -0,0 +1,224 @@
+/* aoc-c.c: Advent of Code 2019, day 3 parts 1 & 2
+ *
+ * Copyright (C) 2021 Bruno Raoult ("br")
+ * Licensed under the GNU General Public License v3.0 or later.
+ * Some rights reserved. See COPYING.
+ *
+ * You should have received a copy of the GNU General Public License along with this
+ * program. If not, see <https://www.gnu.org/licenses/gpl-3.0-standalone.html>.
+ *
+ * SPDX-License-Identifier: GPL-3.0-or-later <https://spdx.org/licenses/GPL-3.0-or-later.html>
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <unistd.h>
+#include <errno.h>
+#include <string.h>
+
+#include "br.h"
+#include "bits.h"
+#include "debug.h"
+#include "list.h"
+#include "pool.h"
+#include "debug.h"
+
+typedef enum { DOWN = 'D', LEFT = 'L', RIGHT = 'R', UP = 'U' } dir_t;
+
+struct point {
+    int x, y;
+};
+
+struct wire {
+    int dist;                                     /* total distance before this wire */
+    struct point delta;                           /* current delta */
+    struct point p0, p1;
+    struct list_head list;                        /* wire list */
+};
+
+static struct wires {
+    int nwires[2];
+    struct list_head head[2];
+} wires[2];
+
+static pool_t *wire_pool;
+
+static struct wires *parse()
+{
+    size_t alloc = 0;
+    ssize_t buflen;
+    char *buf = NULL, *token;
+
+    /* initialize wires lists */
+    INIT_LIST_HEAD(&wires->head[0]);
+    INIT_LIST_HEAD(&wires->head[1]);
+
+    for (int line = 0; line < 2; ++line) {
+        int x0 = 0, y0 = 0;
+        int x1 = 0, y1 = 0;
+        int totdist = 0;
+
+        if ((buflen = getline(&buf, &alloc, stdin)) <= 0) {
+            fprintf(stderr, "error %d reading file.\n", errno);
+            goto end;
+        }
+
+        for (token = strtok(buf, ","); token; token = strtok(NULL, ",")) {
+            dir_t dir = *token;
+            int dist = atoi(token + 1);
+            struct wire *new = pool_get(wire_pool);
+            INIT_LIST_HEAD(&new->list);
+            new->dist = totdist;
+            new->delta.x = 0;
+            new->delta.y = 0;
+            totdist += abs(dist);
+            switch(dir) {
+                case DOWN:
+                    y1 = y0 - dist;
+                    new->delta.y = -dist;
+                    break;
+                case UP:
+                    y1 = y0 + dist;
+                    new->delta.y = dist;
+                    break;
+                case LEFT:
+                    x1 = x0 - dist;
+                    new->delta.x = -dist;
+                    break;
+                case RIGHT:
+                    x1 = x0 + dist;
+                    new->delta.x = dist;
+            }
+            new->p0.x = min(x0, x1);
+            new->p0.y = min(y0, y1);
+            new->p1.x = max(x0, x1);
+            new->p1.y = max(y0, y1);
+            list_add_tail(&new->list, &wires->head[line]);
+            x0 = x1;
+            y0 = y1;
+            wires->nwires[line]++;
+        }
+    }
+end:
+    free(buf);
+    return wires;
+}
+
+#define manhattan(x, y) (abs(x) + abs(y))
+
+static struct point *intersect(struct wire *w1, struct wire *w2, struct point *ret)
+{
+    log_f(3, "(%d,%d)-(%d,%d) (%d,%d)-(%d,%d): ",
+          w1->p0.x, w1->p0.y, w1->p1.x, w1->p1.y,
+          w2->p0.x, w2->p0.y, w2->p1.x, w2->p1.y);
+    if (w1->p0.x == w1->p1.x) {                       /* w1 vertical */
+        /* TODO: overlapping wires (multiple intersections) */
+        if (w1->p0.x >= w2->p0.x && w1->p1.x <= w2->p1.x &&
+            w1->p0.y <= w2->p0.y && w1->p1.y >= w2->p1.y) {
+            log(3, "intersect 1 at (%d, %d)\n", w1->p0.x, w2->p0.y);
+            ret->x = w1->p0.x;
+            ret->y = w2->p0.y;
+            return ret;
+            //return manhatan(w1->p0.x, w2->p0.y);
+        }
+        log(3, "no intersection\n");
+        return NULL;
+    } else {                                      /* w1 horizontal */
+        if (w1->p0.x <= w2->p0.x && w1->p1.x >= w2->p1.x &&
+            w1->p0.y <= w2->p1.y && w1->p1.y >= w2->p0.y) {
+            log(3, "intersect 2 at (%d, %d)\n", w2->p0.x, w1->p0.y);
+            ret->x = w2->p0.x;
+            ret->y = w1->p0.y;
+            return ret;
+            //return manhatan(w2->p0.x, w1->p0.y);
+        }
+        log(3, "no intersection\n");
+        return NULL;
+    }
+}
+
+static s32 part1(struct wires *w)
+{
+    struct wire *w0, *w1;
+    struct point cross;
+    s32 res = INT32_MAX;
+
+    list_for_each_entry(w0, &w->head[0], list) {
+        list_for_each_entry(w1, &w->head[1], list) {
+            if (intersect(w0, w1, &cross)) {
+                int tmp = manhattan(cross.x, cross.y);
+                log(3, "new manhattan: %d\n", tmp);
+                res = min(tmp, res);
+            }
+        }
+    }
+    return res;
+}
+
+static int part2(struct wires *w)
+{
+    struct wire *w0, *w1;
+    struct point cross;
+    s32 res = INT32_MAX;
+
+    list_for_each_entry(w0, &w->head[0], list) {
+        list_for_each_entry(w1, &w->head[1], list) {
+            if (intersect(w0, w1, &cross)) {
+                if (cross.x || cross.y) {
+                    int tmp = w0->dist + w1->dist;
+
+                    /* as w->p0 contains the lowest value of (x, y), we lost the
+                     * starting point information. We adjust remaining steps with
+                     * the delta sign, which indicates if we swapped p0 and p1.
+                     */
+                    tmp += w0->delta.x + w0->delta.y > 0 ?
+                        abs(cross.x - w0->p0.x) + abs(cross.y - w0->p0.y) :
+                        abs(cross.x - w0->p1.x) + abs(cross.y - w0->p1.y);
+                    tmp += w1->delta.x + w1->delta.y > 0 ?
+                        abs(cross.x - w1->p0.x) + abs(cross.y - w1->p0.y) :
+                        abs(cross.x - w1->p1.x) + abs(cross.y - w1->p1.y);
+                    /*  new best */
+                    res = min(tmp, res);
+                }
+            }
+        }
+    }
+    return res;
+}
+
+static int usage(char *prg)
+{
+    fprintf(stderr, "Usage: %s [-d debug_level] [-p part]\n", prg);
+    return 1;
+}
+
+int main(int ac, char **av)
+{
+    int opt, part = 1;
+    struct wires *wires;
+
+    while ((opt = getopt(ac, av, "d:p:")) != -1) {
+        switch (opt) {
+            case 'd':
+                debug_level_set(atoi(optarg));
+                break;
+            case 'p':                             /* 1 or 2 */
+                part = atoi(optarg);
+                if (part < 1 || part > 2)
+                    return usage(*av);
+                break;
+            default:
+                return usage(*av);
+        }
+    }
+
+    if (optind < ac)
+        return usage(*av);
+    wire_pool = pool_create("wire", 256, sizeof(struct wire));
+
+    wires = parse();
+    printf("%s : res=%d\n", *av, part == 1? part1(wires): part2(wires));
+    pool_destroy(wire_pool);
+    exit (0);
+}

2019/include/br.h

@@ -0,0 +1,203 @@
+/* bits.h - bits functions.
+ *
+ * Copyright (C) 2021-2022 Bruno Raoult ("br")
+ * Licensed under the GNU General Public License v3.0 or later.
+ * Some rights reserved. See COPYING.
+ *
+ * You should have received a copy of the GNU General Public License along with this
+ * program. If not, see <https://www.gnu.org/licenses/gpl-3.0-standalone.html>.
+ *
+ * SPDX-License-Identifier: GPL-3.0-or-later <https://spdx.org/licenses/GPL-3.0-or-later.html>
+ *
+ * Some parts are taken from Linux's kernel <linux/kernel.h> and others, and are :
+ * SPDX-License-Identifier: GPL-2.0
+ *
+ * This header contains generic stuff.
+ */
+
+#ifndef _BR_H
+#define _BR_H
+
+/* generate a (maybe) unique id.
+ */
+#define ___PASTE(x, y)      x##y
+#define __PASTE(x, y)       ___PASTE(x, y)
+#define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__)
+//__##prefix##__COUNTER__
+
+/* see https://lkml.org/lkml/2018/3/20/845 for explanation of this monster
+ */
+#define __is_constexpr(x) \
+	(sizeof(int) == sizeof(*(8 ? ((void *)((long)(x) * 0l)) : (int *)8)))
+
+/*
+ * min()/max()/clamp() macros must accomplish three things:
+ *
+ * - avoid multiple evaluations of the arguments (so side-effects like
+ *   "x++" happen only once) when non-constant.
+ * - perform strict type-checking (to generate warnings instead of
+ *   nasty runtime surprises). See the "unnecessary" pointer comparison
+ *   in __typecheck().
+ * - retain result as a constant expressions when called with only
+ *   constant expressions (to avoid tripping VLA warnings in stack
+ *   allocation usage).
+ */
+#define __typecheck(x, y) \
+	(!!(sizeof((typeof(x) *)1 == (typeof(y) *)1)))
+
+#define __no_side_effects(x, y) \
+		(__is_constexpr(x) && __is_constexpr(y))
+
+#define __safe_cmp(x, y) \
+		(__typecheck(x, y) && __no_side_effects(x, y))
+
+#define __cmp(x, y, op)	((x) op (y) ? (x) : (y))
+
+#define __cmp_once(x, y, unique_x, unique_y, op) ({	\
+		typeof(x) unique_x = (x);		\
+		typeof(y) unique_y = (y);		\
+		__cmp(unique_x, unique_y, op); })
+
+#define __careful_cmp(x, y, op) \
+	__builtin_choose_expr(__safe_cmp(x, y), \
+		__cmp(x, y, op), \
+		__cmp_once(x, y, __UNIQUE_ID(__x), __UNIQUE_ID(__y), op))
+
+/**
+ * min - return minimum of two values of the same or compatible types
+ * @x: first value
+ * @y: second value
+ */
+#define min(x, y)	__careful_cmp(x, y, <)
+
+/**
+ * max - return maximum of two values of the same or compatible types
+ * @x: first value
+ * @y: second value
+ */
+#define max(x, y)	__careful_cmp(x, y, >)
+
+/**
+ * min3 - return minimum of three values
+ * @x: first value
+ * @y: second value
+ * @z: third value
+ */
+#define min3(x, y, z) min((typeof(x))min(x, y), z)
+
+/**
+ * max3 - return maximum of three values
+ * @x: first value
+ * @y: second value
+ * @z: third value
+ */
+#define max3(x, y, z) max((typeof(x))max(x, y), z)
+
+/**
+ * min_not_zero - return the minimum that is _not_ zero, unless both are zero
+ * @x: value1
+ * @y: value2
+ */
+#define min_not_zero(x, y) ({			\
+	typeof(x) __x = (x);			\
+	typeof(y) __y = (y);			\
+	__x == 0 ? __y : ((__y == 0) ? __x : min(__x, __y)); })
+
+/**
+ * clamp - return a value clamped to a given range with strict typechecking
+ * @val: current value
+ * @lo: lowest allowable value
+ * @hi: highest allowable value
+ *
+ * This macro does strict typechecking of @lo/@hi to make sure they are of the
+ * same type as @val.  See the unnecessary pointer comparisons.
+ */
+#define clamp(val, lo, hi) min((typeof(val))max(val, lo), hi)
+
+/*
+ * ..and if you can't take the strict
+ * types, you can specify one yourself.
+ *
+ * Or not use min/max/clamp at all, of course.
+ */
+
+/**
+ * min_t - return minimum of two values, using the specified type
+ * @type: data type to use
+ * @x: first value
+ * @y: second value
+ */
+#define min_t(type, x, y)	__careful_cmp((type)(x), (type)(y), <)
+
+/**
+ * max_t - return maximum of two values, using the specified type
+ * @type: data type to use
+ * @x: first value
+ * @y: second value
+ */
+#define max_t(type, x, y)	__careful_cmp((type)(x), (type)(y), >)
+
+/**
+ * clamp_t - return a value clamped to a given range using a given type
+ * @type: the type of variable to use
+ * @val: current value
+ * @lo: minimum allowable value
+ * @hi: maximum allowable value
+ *
+ * This macro does no typechecking and uses temporary variables of type
+ * @type to make all the comparisons.
+ */
+#define clamp_t(type, val, lo, hi) min_t(type, max_t(type, val, lo), hi)
+
+/**
+ * clamp_val - return a value clamped to a given range using val's type
+ * @val: current value
+ * @lo: minimum allowable value
+ * @hi: maximum allowable value
+ *
+ * This macro does no typechecking and uses temporary variables of whatever
+ * type the input argument @val is.  This is useful when @val is an unsigned
+ * type and @lo and @hi are literals that will otherwise be assigned a signed
+ * integer type.
+ */
+#define clamp_val(val, lo, hi) clamp_t(typeof(val), val, lo, hi)
+
+/**
+ * swap - swap values of @a and @b
+ * @a: first value
+ * @b: second value
+ */
+#define swap(a, b) \
+	do { typeof(a) __tmp = (a); (a) = (b); (b) = __tmp; } while (0)
+
+/**
+ * ARRAY_SIZE - get the number of elements in array @arr
+ * @arr: array to be sized
+ */
+#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]))
+
+/**
+ * abs - return absolute value of an argument
+ * @x: the value.  If it is unsigned type, it is converted to signed type first.
+ *     char is treated as if it was signed (regardless of whether it really is)
+ *     but the macro's return type is preserved as char.
+ *
+ * Return: an absolute value of x.
+ */
+#define abs(x)	__abs_choose_expr(x, long long,				\
+		__abs_choose_expr(x, long,				\
+		__abs_choose_expr(x, int,				\
+		__abs_choose_expr(x, short,				\
+		__abs_choose_expr(x, char,				\
+		__builtin_choose_expr(					\
+			__builtin_types_compatible_p(typeof(x), char),	\
+			(char)({ signed char __x = (x); __x<0?-__x:__x; }), \
+			((void)0)))))))
+
+#define __abs_choose_expr(x, type, other) __builtin_choose_expr(	\
+	__builtin_types_compatible_p(typeof(x),   signed type) ||	\
+	__builtin_types_compatible_p(typeof(x), unsigned type),		\
+	({ signed type __x = (x); __x < 0 ? -__x : __x; }), other)
+
+
+#endif  /* _BR_H */