day 8 and day 9

8 files changed, 2359 insertions, 0 deletions

diff --git a/Advent-of-Code-2022/aoc-8/build.sh b/Advent-of-Code-2022/aoc-8/build.sh
new file mode 100755
index 0000000..30f495e
--- /dev/null
+++ b/Advent-of-Code-2022/aoc-8/build.sh
@@ -0,0 +1,5 @@
+#!/bin/sh
+
+set -xe
+
+gcc -o main main.c -Wall -Wextra -pedantic
diff --git a/Advent-of-Code-2022/aoc-8/input.txt b/Advent-of-Code-2022/aoc-8/input.txt
new file mode 100644
index 0000000..e658b1d
--- /dev/null
+++ b/Advent-of-Code-2022/aoc-8/input.txt
@@ -0,0 +1,99 @@
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diff --git a/Advent-of-Code-2022/aoc-8/main.c b/Advent-of-Code-2022/aoc-8/main.c
new file mode 100644
index 0000000..ee36c26
--- /dev/null
+++ b/Advent-of-Code-2022/aoc-8/main.c
@@ -0,0 +1,124 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <assert.h>
+
+#if 0
+  #define PART part1
+#else
+  #define PART part2
+#endif
+
+#if 0
+  #define FILENAME "sample.txt"
+  #define SIDE 5
+#else
+  #define FILENAME "input.txt"
+  #define SIDE 99
+#endif
+
+#define MAX(x, y) (((x) > (y)) ? (x) : (y))
+
+int ans = 0;
+int table[SIDE][SIDE];
+
+void parse()
+{
+    FILE *fp = fopen(FILENAME, "r");
+    if(!fp) {
+        fprintf(stderr, "ERROR: Could not opne file: %s\n", FILENAME);
+        exit(1);
+    }
+
+    char line[256];
+    int col = 0;
+    while(fgets(line, sizeof(line), fp))
+    {
+        assert(col < SIDE);
+
+        for(int i = 0; i < SIDE; i++)
+            table[i][col] = line[i] - '0';
+        col++;
+    }
+
+    fclose(fp);
+}
+
+void part1()
+{
+    ans = (SIDE*4) - 4;
+
+    for(int y = 1; y < (SIDE-1); y++)
+        for(int x = 1; x < (SIDE-1); x++)
+        {
+            int cur = table[x][y];
+
+            // row left
+            int rl = 1;
+            for(int i = 0; i < x; i++)
+                rl &= cur > table[i][y];
+
+            // row right
+            int rr = 1;
+            for(int i = (x+1); i < SIDE; i++)
+                rr &= cur > table[i][y];
+
+            // col up
+            int cu = 1;
+            for(int i = 0; i < y; i++)
+                cu &= cur > table[x][i];
+
+            // col down
+            int cd = 1;
+            for(int i = (y+1); i < SIDE; i++)
+                cd &= cur > table[x][i];
+
+            if(rl || rr || cu || cd) ans++;
+        }
+}
+
+void part2()
+{
+    for(int y = 1; y < (SIDE-1); y++)
+        for(int x = 1; x < (SIDE-1); x++)
+        {
+            int cur = table[x][y];
+
+            // row left
+            int rl = 0;
+            for(int i = (x-1); i >= 0; i--) {
+                rl++;
+                if(cur <= table[i][y]) break;
+            }
+
+            // row right
+            int rr = 0;
+            for(int i = (x+1); i < SIDE; i++) {
+                rr++;
+                if(cur <= table[i][y]) break;
+            }
+
+            // col up
+            int cu = 0;
+            for(int i = (y-1); i >= 0; i--) {
+                cu++;
+                if(cur <= table[x][i]) break;
+            }
+
+            // col down
+            int cd = 0;
+            for(int i = (y+1); i < SIDE; i++) {
+                cd++;
+                if(cur <= table[x][i]) break;
+            }
+
+            ans = MAX(ans, rl * rr * cu * cd);
+        }
+}
+
+int main(void)
+{
+    parse();
+    PART();
+    printf("%d\n", ans);
+    return 0;
+}
diff --git a/Advent-of-Code-2022/aoc-8/sample.txt b/Advent-of-Code-2022/aoc-8/sample.txt
new file mode 100644
index 0000000..16d6fbd
--- /dev/null
+++ b/Advent-of-Code-2022/aoc-8/sample.txt
@@ -0,0 +1,5 @@
+30373
+25512
+65332
+33549
+35390
diff --git a/Advent-of-Code-2022/aoc-9/build.sh b/Advent-of-Code-2022/aoc-9/build.sh
new file mode 100755
index 0000000..30f495e
--- /dev/null
+++ b/Advent-of-Code-2022/aoc-9/build.sh
@@ -0,0 +1,5 @@
+#!/bin/sh
+
+set -xe
+
+gcc -o main main.c -Wall -Wextra -pedantic
diff --git a/Advent-of-Code-2022/aoc-9/input.txt b/Advent-of-Code-2022/aoc-9/input.txt
new file mode 100644
index 0000000..b9aa23e
--- /dev/null
+++ b/Advent-of-Code-2022/aoc-9/input.txt
@@ -0,0 +1,2000 @@
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+U 16
+L 6
+U 12
+L 8
diff --git a/Advent-of-Code-2022/aoc-9/main.c b/Advent-of-Code-2022/aoc-9/main.c
new file mode 100644
index 0000000..00945eb
--- /dev/null
+++ b/Advent-of-Code-2022/aoc-9/main.c
@@ -0,0 +1,113 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#if 0
+  #define KNOTS 2
+#else
+  #define KNOTS 10
+#endif
+
+#if 0
+  #define FILENAME "sample.txt"
+#else
+  #define FILENAME "input.txt"
+#endif
+
+#define SIDE 1000
+#define OFFSET (SIDE/2)
+
+typedef enum {
+    NONE = 0,
+    NORTH = 1,
+    SOUTH = -1,
+    EAST = 1,
+    WEST = -1
+} direction;
+
+int board[SIDE][SIDE] = {0};
+int rope[KNOTS][2] = {0};
+direction rope_dir[KNOTS][2] = {0};
+
+void move(int k)
+{
+    rope[k][0] += rope_dir[k][0];
+    rope[k][1] += rope_dir[k][1];
+}
+
+void parse_dir(char d)
+{
+    rope_dir[0][0] = NONE;
+    rope_dir[0][1] = NONE;
+
+    switch(d) {
+    case 'U':
+        rope_dir[0][1] = NORTH;
+        return;
+    case 'D':
+        rope_dir[0][1] = SOUTH;
+        return;
+    case 'R':
+        rope_dir[0][0] = EAST;
+        return;
+    case 'L':
+        rope_dir[0][0] = WEST;
+        return;
+    }
+}
+
+void parse()
+{
+    FILE *fp = fopen(FILENAME, "r");
+    if(!fp) {
+        fprintf(stderr, "ERROR: Could not open file: %s\n", FILENAME);
+        exit(1);
+    }
+
+    char line[256];
+    while(fgets(line, sizeof(line), fp))
+    {
+        parse_dir(strtok(line, " ")[0]);
+        int n = atoi(strtok(NULL, " "));
+
+        for(int i = 0; i < n; i++)
+        {
+            move(0);
+            for(int j = 1; j < KNOTS; j++)
+            {
+                int hor  = rope[j-1][0] - rope[j][0];
+                if(hor > 0) rope_dir[j][0] = EAST;
+                else if(hor < 0) rope_dir[j][0] = WEST;
+                else rope_dir[j][0] = NONE;
+
+                int vert = rope[j-1][1] - rope[j][1];
+                if(vert > 0) rope_dir[j][1] = NORTH;
+                else if(vert < 0) rope_dir[j][1] = SOUTH;
+                else rope_dir[j][1] = NONE;
+
+                if(abs(vert) > 1 || abs(hor) > 1)
+                    move(j);
+            }
+
+            board[rope[KNOTS-1][0] + OFFSET][rope[KNOTS-1][1] + OFFSET]++;
+        }
+    }
+
+    fclose(fp);
+}
+
+int sum()
+{
+    int sum = 0;
+    for(int i = 0; i < SIDE; i++)
+        for(int j = 0; j < SIDE; j++)
+            if(board[j][i] > 0) sum++;
+    return sum;
+}
+
+int main(void)
+{
+    parse();
+    printf("%d\n", sum());
+    return 0;
+}
diff --git a/Advent-of-Code-2022/aoc-9/sample.txt b/Advent-of-Code-2022/aoc-9/sample.txt
new file mode 100644
index 0000000..60bd43b
--- /dev/null
+++ b/Advent-of-Code-2022/aoc-9/sample.txt
@@ -0,0 +1,8 @@
+R 5
+U 8
+L 8
+D 3
+R 17
+D 10
+L 25
+U 20