C++算法库 (3)划分操作

/*is_partitioned   检测某个范围是否按指定谓词划分过*/
#include 
  
   
#include 
   
     #include 
    
      using namespace std; bool IsOdd(int i) {return (i % 2) == 1;} int main(int argc, const char * argv[]) { array
     
       foo = {1,2,3,4,5,6,7}; //print contents: cout<<"foo:"; for (int& x:foo) cout<<" "<
       
       

 
 
       
输出结果：
 
 
       
foo: 1 2 3 4 5 6 7 (not partitioned)
foo: 1 7 3 5 4 6 2 (partitioned)
       
 
       

 
 
       
 
       
/*partition   将某个范围划分为两组*/
#include 
        
         
#include 
         
           #include 
          
            using namespace std; bool IsOdd(int i) {return (i % 2) == 1;} int main(int argc, const char * argv[]) { vector
           
             myvector; vector
            
             ::iterator it; //set some values: for (int i = 1; i < 10; ++i) myvector.push_back(i); vector
             
              ::iterator bound; bound = partition(myvector.begin(), myvector.end(), IsOdd); //print out content: cout<<"odd elements:"; for (it = myvector.begin(); it != bound; ++it) cout<<" "<<*it; cout<
               
               

 
 
               
输出结果：
 
 
               
odd elements: 1 9 3 7 5
even elements: 6 4 8 2
               
 
               
 
               
 
               
 
               
/*partition_copy   拷贝指定范围的划分结果*/
#include 
                
                 
#include 
                 
                   #include 
                  
                    using namespace std; bool IsOdd(int i) {return (i % 2) == 1;} int main(int argc, const char * argv[]) { vector
                   
                     foo; vector
                    
                      odd,even; vector
                     
                      ::iterator it; //set some values: for (int i = 1; i < 10; ++i) foo.push_back(i); unsigned n = (unsigned)count_if(foo.begin(), foo.end(), IsOdd); odd.resize(n); even.resize(foo.size() - n); //partition: partition_copy(foo.begin(), foo.end(), odd.begin(), even.begin(), IsOdd); //print contents: cout<<"odd: "; for (int& x:odd) cout<<" "<
                       
                       
 
                       
输出结果：
 





 
                       
 
                       
odd:  1 3 5 7 9
even:  2 4 6 8

                       
 
                       
 
                       
 
                       

                       
/*partition_point    返回被划分范围的划分点*/
#include 
                        
                         
#include 
                         
                           #include 
                          
                            using namespace std; bool IsOdd(int i) {return (i % 2) == 1;} int main(int argc, const char * argv[]) { vector
                           
                             foo; vector
                            
                              odd; //set some values: for (int i = 1; i < 10; ++i) foo.push_back(i); partition(foo.begin(), foo.end(), IsOdd); auto it = partition_point(foo.begin(), foo.end(), IsOdd); odd.assign(foo.begin(), it); //print contents of odd: cout<<"odd:"; for (int& x:odd) cout<<" "<
                             
                              
 
                              
 
                              
 
                              
输出结果：
 
                              

                              
odd: 1 9 3 7 5

                              
 
                              
/*stable_partition    稳定划分，两组元素各维持相对顺序*/
#include 
                               
                                
#include 
                                
                                  #include 
                                 
                                   using namespace std; bool IsOdd(int i) {return (i % 2) == 1;} int main(int argc, const char * argv[]) { vector
                                  
                                    myvector; vector
                                   
                                    ::iterator it; vector
                                    
                                     ::iterator bound; for (int i = 1; i < 10; ++i) myvector.push_back(i); bound = stable_partition(myvector.begin(), myvector.end(), IsOdd); //print out content: cout<<"odd elements:"; for (it = myvector.begin(); it != bound ; ++it) cout<<" "<<*it; cout<
                                     
                                      
 
                                      

 
 输出结果：
                                      
 
                                      
odd elements: 1 3 5 7 9
even elements: 2 4 6 8