blob: dbc23529692750b27e0859813894907651076b41 (
plain) (
blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
|
#include <stdio.h>
#include <stdlib.h>
static struct Point {
int x, y;
} Point(int x, int y) {
return (struct Point) { x, y };
}
static int eq(struct Point a, struct Point b) {
return a.x == b.x && a.y == b.y;
}
static struct Point sub(struct Point a, struct Point b) {
return Point(a.x - b.x, a.y - b.y);
}
static struct Point reduce(struct Point p) {
int max = (abs(p.x) > abs(p.y) ? abs(p.x) : abs(p.y));
for (int i = max; i > 1; --i) {
if (p.x / i * i != p.x) continue;
if (p.y / i * i != p.y) continue;
return Point(p.x / i, p.y / i);
}
return p;
}
int main(void) {
struct Point ps[2048];
size_t len = 0;
int y = 0, x = 0;
int ch;
while (EOF != (ch = getchar())) {
switch (ch) {
break; case '.': x++;
break; case '#': ps[len++] = Point(x++, y);
break; case '\n': y++; x = 0;
}
}
size_t max = 0;
for (size_t i = 0; i < len; ++i) {
struct Point ds[2048];
size_t dlen = 0;
for (size_t j = 0; j < len; ++j) {
if (j == i) continue;
struct Point a = reduce(sub(ps[j], ps[i]));
size_t d;
for (d = 0; d < dlen; ++d) {
if (eq(ds[d], a)) break;
}
if (d == dlen) ds[dlen++] = a;
}
if (dlen > max) max = dlen;
}
printf("%zu\n", max);
}
|