| #include <cstdio> |
| #include <cstring> |
| #include <vector> |
| using namespace std; |
|
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|
|
| #define MAXN 700 |
|
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|
|
| typedef unsigned char uch; |
| typedef unsigned int u32; |
|
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| |
| |
| |
| #define HASHB 4096 |
| const size_t KeySz = sizeof(int) * 2; |
| struct HM { |
| struct Key { |
| int d[2]; |
| Key(int *D) { memcpy(d, D, KeySz); } |
| bool operator==(const Key &x) const { |
| return memcmp(d, x.d, KeySz) == 0; } |
| }; |
| struct KV { |
| Key k; int v; |
| KV(const Key &K, int V) : k(K), v(V) {} |
| }; |
| typedef vector<KV> KVV; KVV b[HASHB]; |
| u32 fnv_hash(const Key &k, int len) const { |
| uch *p = reinterpret_cast<uch*>(const_cast<int*>(k.d)); |
| u32 h = 2166136261U; |
| for (int i = 0; i < len; ++i) h = (h * 16777619U) ^ p[i]; |
| return h; |
| } |
| int add(const Key &k) { |
| int i = fnv_hash(k, KeySz) % HASHB; |
| for (int j = 0, J = b[i].size(); j < J; ++j) |
| if (b[i][j].k == k) |
| return ++b[i][j].v; |
| b[i].push_back(KV(k, 2)); |
| return 2; |
| return true; |
| } |
| }; |
|
|
|
|
| template<typename T> |
| T gcd(T a, T b) { for (T c = a%b; c != 0; a=b,b=c,c=a%b); return b; } |
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|
|
| int n; |
| int pts[MAXN][2]; |
|
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|
|
| int solve() |
| { |
| if (n <= 2) return n; |
| int ans = 0; |
|
|
| int m[2]; |
|
|
| for (int i = 0; i < n; ++i) { |
| HM hm; |
|
|
| for (int j = i + 1; j < n; ++j) { |
| if (pts[i][0] == pts[j][0]) |
| m[0] = m[1] = 0; |
| else { |
| m[0] = pts[j][1] - pts[i][1]; |
| m[1] = pts[j][0] - pts[i][0]; |
|
|
| int g = gcd(m[0], m[1]); |
| m[0] /= g; |
| m[1] /= g; |
| } |
|
|
| int coll = hm.add(HM::Key(m)); |
| if (coll > ans) ans = coll; |
| } |
| } |
|
|
| return ans; |
| } |
|
|
| int main() |
| { |
| int T; |
| scanf("%d", &T); |
|
|
| int ncase = 0; |
| while (T--) { |
| scanf("%d", &n); |
|
|
| for (int i = 0; i < n; ++i) |
| scanf("%d%d", &pts[i][0], &pts[i][1]); |
|
|
| printf("Case %d: %d\n", ++ncase, solve()); |
| } |
|
|
| return 0; |
| } |
|
|
