1 files changed, 58 insertions, 0 deletions
diff --git a/16/day3/nickname.cpp b/16/day3/nickname.cpp
new file mode 100644
index 0000000..7e28696
--- /dev/null
+++ b/16/day3/nickname.cpp
@@ -0,0 +1,58 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+vector<int> suffix_array(string& S) {
+	int N = S.length();
+	vector<int> SA(N), rank(N);
+	for (int i = 0; i < N; i++) {
+		SA[i] = N - i - 1;
+		rank[i] = S[i];
+	}
+	stable_sort(SA.begin(), SA.end(), [&S](int i, int j) { return S[i] < S[j]; });
+	for (int t = 1; t < N; t <<= 1) {
+		vector<int> tmp(rank);
+		for (int i = 0; i < N; i++) {
+			bool s = i && SA[i - 1] + t < N && tmp[SA[i]] == tmp[SA[i - 1]] && tmp[SA[i] + (t >> 1)] == tmp[SA[i - 1] + (t >> 1)];
+			rank[SA[i]] = s ? rank[SA[i - 1]] : i;
+		}
+		tmp = SA;
+		vector<int> cnt(N);
+		for (int i = 0; i < N; i++) cnt[i] = i;
+		for (int i = 0; i < N; i++) {
+			if (tmp[i] >= t) SA[cnt[rank[tmp[i] - t]]++] = tmp[i] - t;
+		}
+	}
+	return SA;
+}
+
+vector<int> lcp_array(const vector<int>& SA, string& S) {
+	int N = S.size();
+	vector<int> rank(N), LCP(N - 1);
+	for (int i = 0; i < N; i++) rank[SA[i]] = i;
+	int pre = 0;
+	for (int i = 0; i < N; i++) {
+		if (rank[i] < N - 1) {
+			int j = SA[rank[i] + 1];
+			while (max(i, j) + pre < S.size() && S[i + pre] == S[j + pre]) pre++;
+			LCP[rank[i]] = pre;
+			if (pre > 0) pre--;
+		}
+	}
+	return LCP;
+}
+
+int main() {
+	int A, B;
+	string X, Y;
+	cin >> A >> B >> X >> Y;
+	string S = X + '$' + Y;
+	vector<int> SA = suffix_array(S);
+	vector<int> L = lcp_array(SA, S);
+	int ans = 0;
+	for (int i = 0; i < S.size() - 1; ++i) {
+		if ((SA[i] < A && SA[i + 1] > A) || (SA[i] > A && SA[i + 1] < A)) {
+			ans = max(L[i], ans);
+		}
+	}
+	cout << ans << '\n';
+}
+\ No newline at end of file