简单记录下我的学习过程 (代码为主)
//所有容器适用//所有容器适用
random_shuffle(b,e) //随机重排
random_shuffle(b,e,rand)
partition(b,e,p) //分区(不稳定)
stable_partition(b,e,p) //稳定分区,相对顺序不变。
//返回值,为第一个分区的最后一个的后一个位置,也可以说是下个分区的起始位置!
/**------http://blog.csdn.net/u010579068------**/ #include<iostream> #include<cstdio> #include<string> #include<vector> #include<list> #include<ctime> #include<deque> #include<algorithm> using namespace std; /***************************************** //所有容器适用 random_shuffle(b,e) //随机重排 random_shuffle(b,e,rand) partition(b,e,p) //分区(不稳定) stable_partition(b,e,p) //稳定分区,相对顺序不变。 //返回值,为第一个分区的最后一个的后一个位置,也可以说是下个分区的起始位置! *****************************************/ /**---------------------------------------------------------------------------------- ----------------------------------------------------------------------------------**/ /************************************************************************************* std::random_shuffle 所有排序容器适用 algorithm -------------------------------------------------------------------------------------- template <class RandomAccessIterator> void random_shuffle ( RandomAccessIterator first, RandomAccessIterator last ); template <class RandomAccessIterator, class RandomNumberGenerator> void random_shuffle ( RandomAccessIterator first, RandomAccessIterator last, RandomNumberGenerator& rand ); //eg: template <class RandomAccessIterator, class RandomNumberGenerator> void random_shuffle ( RandomAccessIterator first, RandomAccessIterator last, RandomNumberGenerator& rand ) { iterator_traits<RandomAccessIterator>::difference_type i, n; n = (last-first); for (i=n-1; i>0; --i) swap (first[i],first[rand(i+1)]); } *************************************************************************************/ /************************************************************************************* std::partition 所有排序容器适用 algorithm -------------------------------------------------------------------------------------- template <class BidirectionalIterator, class Predicate> BidirectionalIterator partition ( BidirectionalIterator first, BidirectionalIterator last, Predicate pred ); //eg: template <class BidirectionalIterator, class Predicate> BidirectionalIterator partition ( BidirectionalIterator first, BidirectionalIterator last, Predicate pred ) { while (true) { while (first!=last && pred(*first)) ++first; if (first==last--) break; while (first!=last && !pred(*last)) --last; if (first==last) break; swap (*first++,*last); } return first; } *************************************************************************************/ /************************************************************************************* std::stable_partition 所有排序容器适用 algorithm -------------------------------------------------------------------------------------- template <class BidirectionalIterator, class Predicate> BidirectionalIterator stable_partition ( BidirectionalIterator first, BidirectionalIterator last, Predicate pred ); //eg: *************************************************************************************/ // random generator function: ptrdiff_t myrandom (ptrdiff_t i) { return rand()%i; } // pointer object to it: ptrdiff_t (*p_myrandom)(ptrdiff_t) = myrandom; template <typename T> void Print(T& V) { typename T::iterator iter=V.begin(); while(iter != V.end()) { cout<< *iter++ << " "; } cout<<endl; } int main () { /**---------------------随机重排----------------------**/ srand (unsigned(time(NULL))); vector<int> myvector; vector<int>::iterator it; // set some values: for (int i=1; i<10; ++i) myvector.push_back(i); // 1 2 3 4 5 6 7 8 9 // using built-in random generator: random_shuffle ( myvector.begin(), myvector.end() ); cout << "myvector random_shuffle 1 contains:"; Print(myvector); // using myrandom: random_shuffle ( myvector.begin(), myvector.end(), p_myrandom); // print out content: cout << "myvector random_shuffle 2 contains:"; Print(myvector); cout << endl; /**-----------------------分区------------------------**/ deque<int> mydeque; deque<int>::iterator id, bound; // set some values: for (int i=1; i<10; ++i) mydeque.push_back(i); // 1 2 3 4 5 6 7 8 9 bound = partition (mydeque.begin(), mydeque.end(), bind2nd(modulus<int>(),2)); // print out content: cout << "odd members:"; for (id=mydeque.begin(); id!=bound; ++id) cout << " " << *id; cout << "\neven members:"; for (id=bound; id!=mydeque.end(); ++id) cout << " " << *id; cout << endl << endl; /**---------------------稳定分区----------------------**/ int m[]={1,4,3,2,9,6,7,8,5}; list<int> mylist(m,m+9); list<int>::iterator il, lbound; // set some values: // for (int i=1; i<10; ++i) mylist.push_back(i); // 1 2 3 4 5 6 7 8 9 lbound = stable_partition (mylist.begin(), mylist.end(), bind2nd(modulus<int>(),2)); // print out content: cout << "odd members:"; for (il=mylist.begin(); il!=lbound; ++il) cout << " " << *il; cout << "\neven members:"; for (il=lbound; il!=mylist.end(); ++il) cout << " " << *il; cout << endl; return 0; }
myvector random_shuffle 1 contains:6 4 9 7 1 8 3 5 2 myvector random_shuffle 2 contains:3 4 2 6 9 7 8 5 1 odd members: 1 9 3 7 5 even members: 6 4 8 2 odd members: 1 3 9 7 5 even members: 4 2 6 8