1 files changed, 71 insertions, 0 deletions
diff --git a/15/day3/camelot.cpp b/15/day3/camelot.cpp
new file mode 100644
index 0000000..ea96663
--- /dev/null
+++ b/15/day3/camelot.cpp
@@ -0,0 +1,71 @@
+#include <bits/stdc++.h>
+#define f first
+#define s second
+using namespace std;
+using ll = long long;
+using ii = pair<int, int>;
+
+const int dx[] = { 2, 1, -1, -2, -2, -1, 1, 2 };
+const int dy[] = { 1, 2, 2, 1, -1, -2, -2, -1 };
+
+int d[44][44];
+bool b[44][44];
+inline int & dist(int i, int j) { return d[i + 22][j + 22]; }
+inline bool & vis(int i, int j) { return b[i + 22][j + 22]; }
+
+ii P[202];
+int dp[202][101];
+
+int main() {
+	ios_base::sync_with_stdio(0), cin.tie(0);
+
+	int N, R, C;
+	cin >> N >> R >> C;
+	for (int i = 0; i < N; ++i) {
+		cin >> P[i].f >> P[i].s;
+		--P[i].f, --P[i].s;
+	}
+
+	// BFS to compute distances
+	auto valid = [&R, &C](int i, int j) { return i > -R && i < R && j > -C && j < C; };
+	dist(0, 0) = 0;
+	queue<ii> q;
+	q.emplace(0, 0);
+	while (q.size()) {
+		ii u = q.front();
+		q.pop();
+		if (vis(u.f, u.s)) continue;
+		vis(u.f, u.s) = 1;
+		for (int d = 0; d < 8; ++d) {
+			ii v(u.f + dx[d], u.s + dy[d]);
+			if (valid(v.f, v.s) && !vis(v.f, v.s)) {
+				dist(v.f, v.s) = dist(u.f, u.s) + 1;
+				q.push(v);
+			}
+		}
+	}
+
+	// O(R^2 * C^2 * N^2)
+	int ans = 1e9;
+	for (int a = 0; a < R; ++a) {
+		for (int b = 0; b < C; ++b) {
+			for (int c = a; c < R; ++c) {
+				for (int d = 0; d < C; ++d) {
+					if (a == c && b == d) continue;
+					// First meetup location: (a, b)
+					// Second meetup location: (c, d)
+					memset(dp, '?', sizeof dp);
+					dp[0][0] = 0;
+					for (int i = 0; i < N; ++i) {
+						for (int j = 0; j <= min(i, N / 2); ++j) {
+							dp[i + 1][j] = min(dist(P[i].f - a, P[i].s - b) + dp[i][j], dp[i + 1][j]);
+							dp[i + 1][j + 1] = min(dist(P[i].f - c, P[i].s - d) + dp[i][j], dp[i + 1][j + 1]);
+						}
+					}
+					ans = min(dp[N][N / 2], ans);
+				}
+			}
+		}
+	}
+	cout << ans << '\n';
+}
+\ No newline at end of file