plasl day2p1 and a lot of other junk i never pushed

src/c/2024/day20/part2.c

@@ -0,0 +1,224 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define BOARD_SIZE 141
+
+#define CHEAT_LENGTH 20
+
+#define IN_BOUND(x, y) (x < BOARD_SIZE && x >= 0 && y < BOARD_SIZE && y >= 0)
+#define MIN(a,b) (((a)<(b))?(a):(b))
+
+struct coordinate {
+
+    int x, y;
+
+};
+
+
+struct coordinate queue[10000];
+int queue_len;
+int queue_start;
+
+char map[BOARD_SIZE][BOARD_SIZE];
+int values[BOARD_SIZE][BOARD_SIZE];
+
+struct coordinate cheat_deltas[10000];
+int num_cheat_deltas;
+
+
+int queue_pop(struct coordinate *coord) {
+
+    if (queue_len == 0) {
+        return -1;
+    }
+
+    memcpy(coord, &queue[queue_start], sizeof(struct coordinate));
+
+    queue_start++;
+    queue_len--;
+
+    return 0;
+
+}
+
+
+void queue_push(struct coordinate *coord) {
+
+    
+    //printf("%d, %da\n", coord->x, coord->y);
+
+    memcpy(&queue[queue_start + queue_len], coord, sizeof(struct coordinate));
+    queue_len++;
+
+}
+
+
+void check_and_push(struct coordinate *coord, int depth) {
+
+    //printf("%d\n", depth);
+
+    if (!IN_BOUND(coord->x, coord->y) || map[coord->x][coord->y] == '#') {
+        return;
+    }
+
+    if (values[coord->x][coord->y] == 100000) {
+        //printf("%d\n", depth);
+        values[coord->x][coord->y] = depth + 1;
+        queue_push(coord);
+
+    }
+
+
+}
+
+int dfs(struct coordinate coord) {
+
+    queue_push(&coord);
+    values[coord.x][coord.y] = 0;
+
+    while (!queue_pop(&coord)) {
+
+        //printf("%d, %d!", coord.x, coord.y);
+
+        int value = values[coord.x][coord.y];
+
+        //printf("%d, %d: %d\n", coord.x, coord.y, values[coord.x][coord.y]);
+
+        coord.x++;
+        check_and_push(&coord, value);
+        coord.x -= 2;
+        check_and_push(&coord, value);
+        coord.x++;
+
+        coord.y++;
+        check_and_push(&coord, value);
+        coord.y -= 2;
+        check_and_push(&coord, value);
+        coord.y++;
+
+
+    }
+
+    return 0;
+}
+
+int cheats = 0;
+
+int test_cheat(int x, int y, int value, int dist) {
+    int v;
+    if (IN_BOUND(x, y) && (map[x][y] == '.' || map[x][y] == 'E') && (v = values[x][y] - value) > dist) {
+        v -= dist;
+        //printf("cheat: %d\n", v, x, y);
+
+        if (v >= 100) {
+            cheats++;
+        }
+
+        return v;
+    }   
+    return 0;
+}
+
+int test_next(int x, int y, int value) {
+    //printf("%d, %d\n", value, values[x][y]);
+    return (IN_BOUND(x, y) && map[x][y] == '.' && values[x][y] - value == 1);
+}
+
+
+int find_cheat(int x, int y) {
+
+    printf("%d, %d ", x, y);
+    printf("%c\n", map[x][y]);
+
+    if (!IN_BOUND(x, y)) {
+        return 0;
+    }
+
+
+    int value = values[x][y];
+    int v;
+
+    for (int i = 0; i < num_cheat_deltas; i++) {
+        //printf("%d, %d\n", x + cheat_deltas[i].x, y + cheat_deltas[i].y);
+        test_cheat(x + cheat_deltas[i].x, y + cheat_deltas[i].y, value, abs(cheat_deltas[i].x) + abs(cheat_deltas[i].y));
+    }
+
+    if (test_next(x + 1, y, value)) {
+        return find_cheat(x + 1, y);
+    }
+    if (test_next(x - 1, y, value)) {
+        return find_cheat(x - 1, y);
+    }
+    if (test_next(x, y + 1, value)) {
+        return find_cheat(x, y + 1);
+    }
+    if (test_next(x, y - 1, value)) {
+        return find_cheat(x, y - 1);
+    }
+
+    return 0;
+
+}
+
+
+
+int main() {
+
+    // calc cheats
+    
+    for (int x = -CHEAT_LENGTH; x <= CHEAT_LENGTH; x++) {
+        for (int y = -CHEAT_LENGTH; y <= CHEAT_LENGTH; y++) {
+
+            if (abs(x) + abs(y) <= CHEAT_LENGTH) {
+                //printf("%d, %d\n", x, y);
+
+                cheat_deltas[num_cheat_deltas].x = x;
+                cheat_deltas[num_cheat_deltas].y = y;
+                num_cheat_deltas++;
+                
+            }
+        }
+    }
+
+    //exit(0);
+
+    char *line_buf = NULL;
+    size_t buffer_size = 100;
+
+    for (int i = 0; i < BOARD_SIZE; i++) {
+        for (int j = 0; j < BOARD_SIZE; j++) {
+            map[i][j] = '.';
+            values[i][j] = 100000;
+        }
+    }
+
+    struct coordinate coords[10000];
+    int num_cords = 0;
+
+    
+    struct coordinate start, end;
+
+    int y = 0;
+    while (getline(&line_buf, &buffer_size, stdin) > 0) {
+        printf(line_buf);
+        for (int x = 0; x < BOARD_SIZE; x++) {
+            map[x][y] = line_buf[x];
+
+            if (line_buf[x] == 'S') {
+                start.x = x;
+                start.y = y;
+            }
+
+            if (line_buf[x] == 'E') {
+                end.x = x;
+                end.y = y;
+            }
+        }
+        y++;
+    }
+
+    dfs(start);
+    find_cheat(start.x, start.y);
+    printf("res: %d", cheats);
+}