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Treaps and Hash Tables Added
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‎Algorithm/63 String Hashing.cpp

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/** Which of the favors of your Lord will you deny ? **/
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#include<bits/stdc++.h>
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using namespace std;
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#define LL long long
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#define PII pair<int,int>
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#define PLL pair<LL,LL>
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#define F first
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#define S second
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#define ALL(x) (x).begin(), (x).end()
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#define READ freopen("alu.txt", "r", stdin)
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#define WRITE freopen("vorta.txt", "w", stdout)
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#ifndef ONLINE_JUDGE
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#define DBG(x) cout << __LINE__ << " says: " << #x << " = " << (x) << endl
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#else
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#define DBG(x)
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#define endl "\n"
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#endif
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template<class T1, class T2>
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ostream &operator <<(ostream &os, pair<T1,T2>&p);
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template <class T>
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ostream &operator <<(ostream &os, vector<T>&v);
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template <class T>
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ostream &operator <<(ostream &os, set<T>&v);
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inline void optimizeIO()
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{
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ios_base::sync_with_stdio(false);
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cin.tie(NULL);
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}
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const int nmax = 2e5+7;
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const int prime = 31;
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const int mod = 1e9+7;
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int p[nmax];
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int prefixHash[nmax];
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/*
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* Modular Arithmetic
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* */
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int MUL(int a,int b)
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{
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a %= mod;
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b %= mod;
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return (1LL*a*b) % mod;
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}
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int ADD(int a,int b)
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{
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a %= mod;
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b %= mod;
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return (1LL*a+b) % mod;
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}
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int MINUS(int a,int b)
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{
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a %= mod;
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b %= mod;
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return (1LL*a-b+mod)%mod;
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}
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void precalc()
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{
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p[0] = 1;
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for(int i=1;i<nmax;i++) p[i] = MUL(p[i-1],prime);
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}
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void computePrefixHash(string s) /*prefix hash function*/
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{
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int n = s.size();
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s = "#" + s;
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for(int i=1;i<=n;i++) prefixHash[i] = ADD(prefixHash[i-1],MUL(s[i]-'a'+1,p[i-1]));
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}
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int getSubstringHash(int l,int r) /*1 based indexing*/
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{
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int ret = MINUS(prefixHash[r],MUL(prefixHash[l-1],p[r-l+1])); /*substring hash from prefix hash*/
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return ret;
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}
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int32_t main()
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{
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optimizeIO();
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precalc(); /*precalculating prime exponentiations*/
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string s;
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cin>>s;
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computePrefixHash(s);
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int n = s.size();
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s = "#" + s;
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return 0;
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}
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/**
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**/
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template<class T1, class T2>
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ostream &operator <<(ostream &os, pair<T1,T2>&p)
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{
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os<<"{"<<p.first<<", "<<p.second<<"} ";
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return os;
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}
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template <class T>
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ostream &operator <<(ostream &os, vector<T>&v)
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{
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os<<"[ ";
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for(T i:v)
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{
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os<<i<<" " ;
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}
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os<<" ]";
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return os;
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}
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template <class T>
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ostream &operator <<(ostream &os, set<T>&v)
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{
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os<<"[ ";
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for(T i:v)
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{
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os<<i<<" ";
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}
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os<<" ]";
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return os;
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}

‎Data Structure/35 Implicit Treap.cpp

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/** Which of the favors of your Lord will you deny ? **/
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#include<bits/stdc++.h>
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#include <ostream>
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using namespace std;
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#define LL long long
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#define PII pair<int,int>
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#define PLL pair<LL,LL>
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#define F first
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#define S second
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#define ALL(x) (x).begin(), (x).end()
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#define READ freopen("alu.txt", "r", stdin)
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#define WRITE freopen("vorta.txt", "w", stdout)
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#ifndef ONLINE_JUDGE
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#define DBG(x) cout << __LINE__ << " says: " << #x << " = " << (x) << endl
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#else
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#define DBG(x)
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#define endl "\n"
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#endif
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template<class T1, class T2>
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ostream &operator <<(ostream &os, pair<T1,T2>&p);
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template <class T>
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ostream &operator <<(ostream &os, vector<T>&v);
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template <class T>
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ostream &operator <<(ostream &os, set<T>&v);
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inline void optimizeIO()
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{
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ios_base::sync_with_stdio(false);
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cin.tie(NULL);
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}
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const int nmax = 2e5+7;
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#define int long long
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/*
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* Implicit Treap
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* ==============
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* 0 based indexing
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* */
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mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
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int getrand(int a, int b)
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{
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int x = uniform_int_distribution<int>(a, b)(rng);
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return x;
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}
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struct Node
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{
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int data,prior,subTreeSize;
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Node* l;
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Node* r;
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// extra variables to solve problems , change here
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Node(int data)
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{
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this->data = data;
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prior = getrand(-2e9, 2e9);
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subTreeSize = 1;
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l = r = NULL;
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// change here
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}
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friend ostream &operator<<(ostream &os, const Node &node) {
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os << "data: " << node.data << " prior: " << node.prior << " subTreeSize: " << node.subTreeSize;
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return os;
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}
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};
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typedef Node* Treap;
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struct ImplicitTreap
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{
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Treap root;
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ImplicitTreap()
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{
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root = NULL;
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}
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int sz(Treap t)
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{
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return t == NULL ? 0 : t->subTreeSize;
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}
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void update_sz(Treap t)
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{
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if(t) t->subTreeSize = 1 + sz(t->l) + sz(t->r);
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}
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/*Add
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* 1. reset
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* 2. combine
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* 3. push
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* 4. segmentTreeOperation
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* */
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void split(Treap t,Treap &l,Treap &r,int pos,int add = 0)
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{
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if(!t)
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{
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l = NULL;
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r = NULL;
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return;
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}
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int implicit_pos = add + sz(t->l); /*implicit indexing in implicit treap*/
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if(implicit_pos <= pos)
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{
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split(t->r,t->r,r,pos,implicit_pos + 1);
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l = t;
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}
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else
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{
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split(t->l,l,t->l,pos,add);
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r = t;
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}
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update_sz(t); /*update size*/
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}
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void meld(Treap &ret,Treap l,Treap r)
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{
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if(!l || !r)
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{
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if(l) ret = l;
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if(r) ret = r;
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}
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else if(l->prior > r->prior)
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{
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meld(l->r,l->r,r);
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ret = l;
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}
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else
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{
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meld(r->l,l,r->l);
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ret = r;
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}
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update_sz(ret); /*update size*/
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}
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void print(Treap t,int add)
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{
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if(!t) return;
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cout<<*t<<endl;
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print(t->l,add);
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print(t->r,add + sz(t->l) + 1);
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}
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void print()
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{
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print(root,0);
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}
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// operations
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void insert(int val)
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{
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Treap newTreap = new Node(val);
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meld(root,root,newTreap);
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}
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};
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int32_t main()
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{
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optimizeIO();
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int n,q;
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cin>>n>>q;
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ImplicitTreap t;
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vector<int>v(n+1);
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for(int i=1;i<=n;i++) cin>>v[i] , t.insert(v[i]);
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// t.print();
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return 0;
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}
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/**
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**/
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template<class T1, class T2>
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ostream &operator <<(ostream &os, pair<T1,T2>&p)
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{
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os<<"{"<<p.first<<", "<<p.second<<"} ";
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return os;
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}
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template <class T>
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ostream &operator <<(ostream &os, vector<T>&v)
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{
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os<<"[ ";
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for(T i:v)
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{
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os<<i<<" " ;
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}
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os<<" ]";
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return os;
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}
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template <class T>
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ostream &operator <<(ostream &os, set<T>&v)
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{
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os<<"[ ";
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for(T i:v)
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{
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os<<i<<" ";
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}
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os<<" ]";
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return os;
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}

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