40 lines
1.1 KiB
C++
40 lines
1.1 KiB
C++
vector<int> suffix_array(string & S) {
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int N = S.length();
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vector<int> SA(N), rank(N);
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for (int i = 0; i < N; i++) {
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SA[i] = N - i - 1;
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rank[i] = S[i];
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}
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stable_sort(SA.begin(), SA.end(), [& S](int i, int j) { return S[i] < S[j]; });
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for (int t = 1; t < N; t <<= 1) {
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vector<int> tmp(rank);
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for (int i = 0; i < N; i++) {
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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)];
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rank[SA[i]] = s ? rank[SA[i - 1]] : i;
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}
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tmp = SA;
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vector<int> cnt(N);
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for (int i = 0; i < N; i++) cnt[i] = i;
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for (int i = 0; i < N; i++) {
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if (tmp[i] >= t) SA[cnt[rank[tmp[i] - t]]++] = tmp[i] - t;
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}
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}
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return SA;
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}
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vector<int> lcp_array(const vector<int> & SA, string & S) {
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int N = S.size();
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vector<int> rank(N), LCP(N - 1);
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for (int i = 0; i < N; i++) rank[SA[i]] = i;
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int pre = 0;
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for (int i = 0; i < N; i++) {
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if (rank[i] < N - 1) {
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int j = SA[rank[i] + 1];
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while (max(i, j) + pre < S.size() && S[i + pre] == S[j + pre]) pre++;
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LCP[rank[i]] = pre;
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if (pre > 0) pre--;
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}
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}
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return LCP;
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}
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