STL : Standard Template Library

1. STL : Standard Template Library Mario Ynocente Castro UNI-FIIS

4. Notas Los #include no llevan .h #include <cstdio> // new include method #include <vector> // vector container #include <algorithm> // STL algorithms using namespace std; // assume std::

6. Vector vector<int> v(10); for(int i = 0; i < 10; i++) { v[i] = (i+1)*(i+1); } int numero_elementos = v.size(); bool esta_vacio = (v.size()==0); // Evite usar esto bool esta_vacio = ! v.empty();

7. Vector vector<int> v; // ... vector<int> v2(v); vector<int> v3(v.begin(), v.end()); //v3 igual a v2 int data[] = { 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31 }; vector<int> primes(data, data+(sizeof(data) / sizeof(data[0]))); vector<int> v; // ... vector<int> v2(v.begin(), v.begin() + (v.size()/2));

8. Vector vector<int> v; // ... vector<int> v2(v.rbegin()+(v.size()/2), v.rend()); vector<int> v; // ... // Traverse all container, from begin() to end() vector<int>::iterator it; // declaración de un iterador for(it= v.begin(); it != v.end(); it++) { *it++; // Increment the value iterator is pointing to }

9. Vector vector<int> v(20); for(int i = 0; i < v.size(); i++) { v[i] = i+1; } v.resize(25); for(int i = 20; i < 25; i++) { v[i] = i*2; }

10. Vector vector< vector<int> > Matrix; // >> int N, M; // ... vector< vector<int> > Matrix(N, vector<int>(M, -1)); vector<int> v1; // ... vector<int> v2 = v1; vector<int> v3(v1);

11. Búsqueda en Vector vector<int> v; for(int i = 1; i < 100; i++) { v.push_back(i*i); } Vector<int> :: iterator it= find(v.begin(), v.end(), 49); if(it != v.end()) { // ... }

12. Inserción en Vector vector<int> v; // ... v.insert(1, 42); // Insert value 42 after the first vector<int> v; vector<int> v2; // ... v.insert(1,v2.begin(),v2.end());

13. Eliminación en Vector erase(iterator); erase(iterador inicial, iterador final);

14. String string s = &quot;hello&quot;; string s1 = s.substr(0, 3), // &quot;hel&quot; s2 = s.substr(1, 3), // &quot;ell&quot; s3 = s.substr(0, s.length()-1), &quot;hell&quot; s4 = s.substr(1); // &quot;ello&quot;

15. Pair template<typename T1, typename T2> struct pair { T1 first; T2 second; }; pair<string, pair<int,int> > P; string s = P.first; // extraer string int x = P.second.first; // extraer primer entero int y = P.second.second; // extract segundo entero

17. Set set<int> s; for(int i = 1; i <= 100; i++) { s.insert(i); } s.insert(42); // no hace nada for(int i = 2; i <= 100; i += 2) { s.erase(i); // Borrar todos los valores pares } int n = int(s.size()); // n será 50

18. Set if(s.find(42) != s.end()) { // 42 presents in set } else { // 42 not presents in set }

19. Set int data[5] = { 5, 1, 4, 2, 3 }; set<int> S(data, data+5); vector<int> v; // … set<int> s(all(v)); vector<int> v2(all(s));

20. Buscar y Borrar en Set set<int> s; // ... set<int>::iterator it1, it2; it1 = s.find(10); it2 = s.find(100); // Funcionará si it1 e it2 son iteradores válidos s.erase(it1, it2); // 10 será borrado, pero 100 permanecerá

21. Map map<string, int> M; M[&quot;Top&quot;] = 1; M[&quot;Coder&quot;] = 2; M[&quot;SRM&quot;] = 10; int x = M[&quot;Top&quot;] + M[&quot;Coder&quot;]; if(M.find(&quot;SRM&quot;) != M.end()) { M.erase(M.find(&quot;SRM&quot;)); // or even M.erase(&quot;SRM&quot;) }

23. Algorithm i nt data[5] = { 1, 5, 2, 4, 3 }; vector<int> X(data, data+5); int v1 = *max_element(X.begin(), X.end()); int i1 = min_element(X.begin(), X.end()) – X.begin(); int v2 = *max_element(data, data+5); int i3 = min_element(data, data+5) – data;

24. Algorithm vector<int> X; // ... sort(X.begin(), X.end()); // orden ascendente sort(X.rbegin(), X.rend()); // orden descendente vector<int> v; for(int i = 0; i < 10; i++) { v.push_back(i); } do { Solve(..., v); } while(next_permutation(all(v));

25. String Streams void f(const string& s) { istringstream is(s); vector<int> v; int tmp; while(is >> tmp) { v.push_back(tmp); } }

26. String Streams string f(const vector<int>& v) { ostringstream os; for(vector<int>::iterator it=v.begin();it!=v.end();it++){ os << ' ' << *it; } s = os.str(); if(!s.empty()) s = s.substr(1); return s; }