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#include <stdio.h>
#include <stdlib.h>
#include <htable.h>
#include <crc32.h>
typedef struct {
int x;
int y;
} Point;
uint32_t point_hash(void *point) {
return crc32(0, point, sizeof(Point));
}
bool point_eq(void *x, void *y) {
Point *a = x, *b = y;
return (a->x == b->x) && (a->y == b->y);
}
typedef struct {
Point head;
Point tail;
} State;
bool is_adjacent(Point p1, Point p2) {
if (abs(p1.x - p2.x) <= 1 && abs(p2.y - p1.y) <= 1) {
return true;
}
return false;
}
void run_impl(State *s, HTable *record, int dx, int dy) {
Point new = {s->head.x + dx, s->head.y + dy};
if (!is_adjacent(s->tail, new)) {
s->tail = s->head;
htable_insert(record , &(s->tail));
}
s->head = new;
}
void run(State *s, HTable *record, char direction, int step) {
int dx, dy;
switch (direction) {
case 'U':
dx = 0; dy = 1;
break;
case 'D':
dx = 0; dy = -1;
break;
case 'L':
dx = -1; dy = 0;
break;
case 'R':
dx = 1; dy = 0;
break;
default:
return;
}
for (int i = 0; i < step; i++) {
run_impl(s, record, dx, dy);
}
}
int count_htable(HTable *ht) {
int count = 0;
for (void *iter = htable_begin(ht);
iter != NULL;
iter = htable_next(ht, iter)) {
count++;
}
return count;
}
int main() {
FILE *fp = fopen("input", "r");
State state;
state.head = (Point){0, 0};
state.tail = (Point){0, 0};
char direction;
int step;
HTable record;
htable_init(&record, sizeof(Point), -1, point_hash, point_eq);
while (fscanf(fp, "%c %d", &direction, &step) != EOF) {
run(&state, &record, direction, step);
}
int count = count_htable(&record);
printf("%d\n", count);
return 0;
}
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