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GeezerVison is showing github.com — algorithm/string/suffix_array.cc at master · john0xff/algorithm Expand file tree/ Copy pathsuffix_array.ccMore file actions 68 lines (64 loc) · 1.78 KB / Copy pathsuffix_array.ccFile metadata and controls68 lines (64 loc) · 1.78 KB 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 58 59 60 61 62 63 64 65 66 67 68 // // Suffix Array (Manbar and Myers' O(n (log n)^2)) // // Description: // For a string s, tts suffix array is a lexicographically sorted // list of suffixes of s. For example, for s = "abbab", its SA is // 0 ab // 1 abbab // 2 b // 3 bab // 4 bbab // // Algorithm: // Manbar and Myers' doubling algorithm. // Suppose that suffixes are sorted by its first h characters. // Then, the comparison of first 2h characters is computed by // suf(i) <_2h suf(j) == if (suf(i) !=_h suf(j)) suf(i) <_h suf(j) // else suf(i+h) <_h suf(j+h) // // Complexity: // O(n (log n)^2). // If we use radix sort instead of standard sort, // we obtain O(n log n) algorithm. However, it does not improve // practical performance so much. // // Verify: // SPOJ 6409: SARRAY (80 pt) // #include <iostream> #include <vector> #include <cstdio> #include <cstring> #include <algorithm> #include <numeric> #include <functional> using namespace std; #define fst first #define snd second #define all(c) ((c).begin()), ((c).end()) struct suffix_array { int n; vector<int> x; suffix_array(const char *s) : n(strlen(s)), x(n) { vector<int> r(n), t(n); for (int i = 0; i < n; ++i) r[x[i] = i] = s[i]; for (int h = 1; t[n-1] != n-1; h *= 2) { auto cmp = [&](int i, int j) { if (r[i] != r[j]) return r[i] < r[j]; return i+h < n && j+h < n ? r[i+h] < r[j+h] : i > j; }; sort(all(x), cmp); for (int i = 0; i+1 < n; ++i) t[i+1] = t[i] + cmp(x[i], x[i+1]); for (int i = 0; i < n; ++i) r[x[i]] = t[i]; } } int operator[](int i) const { return x[i]; } }; int main() { char s[100010]; scanf("%s", s); suffix_array sary(s); for (int i = 0; i < sary.n; ++i) printf("%d\n", sary[i]); } |
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