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| 1 | +#include <iostream> |
| 2 | +#include <algorithm> |
| 3 | +#include <vector> |
| 4 | +#include <map> |
| 5 | +#include <set> |
| 6 | +#include <climits> |
| 7 | +#include <cstdio> |
| 8 | +#include <cstring> |
| 9 | +#include <cctype> |
| 10 | +#include <cassert> |
| 11 | +#include <cmath> |
| 12 | +#include <queue> |
| 13 | +using namespace std; |
| 14 | + |
| 15 | +#define trace(x) {cerr << #x << "=" << x <<endl;} |
| 16 | +#define trace2(x, y) {cerr << #x << "=" << x << " " << #y << "=" << y <<endl;} |
| 17 | +template <typename T> ostream& operator<<(ostream& os, const vector<T> &p){os << "[ "; for (T x: p) os << x << " "; os << "]" << endl; return os;} |
| 18 | +template <typename T> ostream& operator<<(ostream& os, const set<T> &p){os << "{ "; for (T x: p) os << x << " "; os << "}" << endl; return os;} |
| 19 | +template <typename Tk, typename Tv> ostream& operator<<(ostream& os, const map<Tk, Tv> &p){os << "{ "; for (pair<Tk, Tv> x: p) os << x << " "; os << "}" << endl; return os;} |
| 20 | +template <typename Tk, typename Tv> ostream& operator<<(ostream& os, const pair<Tk, Tv> &p){os << "{" << p.first << ',' << p.second << "}";return os;} |
| 21 | + |
| 22 | +typedef long long ll; |
| 23 | + |
| 24 | +const int MOD = 1000000000+7; |
| 25 | +const int INF = 1000000000+5; |
| 26 | +const int MAX = 200005; |
| 27 | + |
| 28 | +int lgn=0; |
| 29 | +int sa[25][1000005]; |
| 30 | +int rankSuf[1000005]; |
| 31 | +void constructSA(const char s[], int n) { |
| 32 | + cout << s << endl; |
| 33 | + map<int,int> rank; |
| 34 | + for (int i=0; i<n; i++) rank[s[i]]=0; |
| 35 | + int ctr=1; |
| 36 | + for (auto it=rank.begin(); it!=rank.end(); it++) it->second=ctr++; |
| 37 | + int p2=1; |
| 38 | + while (p2<=n) {p2<<=1; lgn++;} |
| 39 | + for (int i=0; i<n; i++) sa[0][i]=rank[s[i]]; |
| 40 | + for (int i=1, l=1; i<=lgn; i++, l<<=1) { |
| 41 | + vector<pair<pair<int,int>,int>> rank; |
| 42 | + for (int j=0; j<n; j++) { |
| 43 | + pair<pair<int,int>, int> r = {{sa[i-1][j], ((j+l<n)?sa[i-1][j+l]:0)}, j}; |
| 44 | + rank.push_back(r); |
| 45 | + } |
| 46 | + sort(rank.begin(), rank.end()); |
| 47 | + for (int j=0, ctr=1; j<n; j++) { |
| 48 | + if (j>0 && (rank[j].first!=rank[j-1].first)) ctr++; |
| 49 | + sa[i][rank[j].second]=ctr; |
| 50 | + } |
| 51 | + } |
| 52 | + for (int i=0; i<n; i++) rankSuf[sa[lgn][i]-1]=i; |
| 53 | +} |
| 54 | + |
| 55 | +int getLCP(int p, int q) { |
| 56 | + int l=0; |
| 57 | + for (int i=lgn, len=(1<<lgn); i>=0; i--, len>>=1) { |
| 58 | + if (sa[i][p]==sa[i][q]) { |
| 59 | + l+=len; p+=len, q+=len; |
| 60 | + } |
| 61 | + } |
| 62 | + return l; |
| 63 | +} |
| 64 | + |
| 65 | +int lcp[25][1000005]; |
| 66 | +void processlcp(int n) { |
| 67 | + int N=n-1; |
| 68 | + for (int i=0; i<N; i++) lcp[0][i]=getLCP(rankSuf[i], rankSuf[i+1]); |
| 69 | + int lgn=0, p2=1; |
| 70 | + while (p2<=N) {p2<<=1; lgn++;} |
| 71 | + for (int i=1,l=1; i<=lgn; i++,l<<=1) { |
| 72 | + for (int j=0; j<n; j++) { |
| 73 | + lcp[i][j] = min(lcp[i-1][j], (j+l<N)?lcp[i-1][j+l]:INF); |
| 74 | + } |
| 75 | + } |
| 76 | +} |
| 77 | + |
| 78 | +int frameSize[MAX]; |
| 79 | +int preprocess(){ |
| 80 | + for(int i=0, pow2=1; pow2 < MAX; pow2*=2, i++) frameSize[pow2]=i; |
| 81 | + for(int i=3;i<MAX;i++) { |
| 82 | + if(frameSize[i]==0) { |
| 83 | + frameSize[i]=frameSize[i-1]; |
| 84 | + } |
| 85 | + } |
| 86 | +} |
| 87 | + |
| 88 | +inline int query(int l, int r){ |
| 89 | + int p = frameSize[r-l+1]; |
| 90 | + return min(lcp[p][l], lcp[p][r-( 1<<p)+ 1]); |
| 91 | +} |
| 92 | + |
| 93 | +int main() { |
| 94 | + string s = "bananan"; |
| 95 | + int n = s.size(); |
| 96 | + constructSA(s.c_str(), n); |
| 97 | + cout << "---" << endl; |
| 98 | + for (int i = 0; i < n; i++) cout << rankSuf[i] << " "; cout << endl; |
| 99 | + for (int i = 0; i < n; i++) cout << s.substr(rankSuf[i]) << endl; |
| 100 | + |
| 101 | + cout << getLCP(1, 3) << endl; |
| 102 | + |
| 103 | + processlcp(n); |
| 104 | + preprocess(); |
| 105 | + cout << query(0, 0) << endl; |
| 106 | +} |
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