Question

这是计算子阵列的最大总和的函数

int Solution::maxSubArray(const vector<int> &A) {
vector<int>::iterator i;


int max_so_far = *A.begin();
int current_max = *A.begin();


for(i = A.begin(); i != A.end(); ++i)
{   
    current_max = max(*i,*i+current_max);
    max_so_far = max(max_so_far,current_max)
}
return max_so_far;

}

这是错误，我得到的是C ++ 11，而不是以前的版本。帮我解决这个问题

solution.cpp: In member function 'int Solution::maxSubArray(const      std::vector<int>&)':
solution.cpp:9:8: error: no match for 'operator=' (operand types are     'std::vector<int>::iterator {aka __gnu_cxx::__normal_iterator<int*,     std::vector<int> >}' and 'std::vector<int>::const_iterator {aka    __gnu_cxx::__normal_iterator<const int*, std::vector<int> >}')
  for(i = A.begin(); i != A.end(); ++i) 
    ^
solution.cpp:9:8: note: candidates are:
In file included from /usr/include/c++/4.8/bits/stl_algobase.h:67:0,
             from /usr/include/c++/4.8/bits/char_traits.h:39,
             from /usr/include/c++/4.8/ios:40,
             from /usr/include/c++/4.8/ostream:38,
             from /usr/include/c++/4.8/iostream:39,
             from solution.h:7,
             from solution.cpp:-3:
/usr/include/c++/4.8/bits/stl_iterator.h:708:11: note:    __gnu_cxx::__normal_iterator<int*, std::vector<int> >&    __gnu_cxx::__normal_iterator<int*, std::vector<int> >::operator=(const   __gnu_cxx::__normal_iterator<int*, std::vector<int> >&)
     class __normal_iterator
            ^
  /usr/include/c++/4.8/bits/stl_iterator.h:708:11: note:   no known      conversion for argument 1 from 'std::vector<int>::const_iterator {aka   __gnu_cxx::__normal_iterator<const int*, std::vector<int> >}' to 'const   __gnu_cxx::__normal_iterator<int*, std::vector<int> >&'
 /usr/include/c++/4.8/bits/stl_iterator.h:708:11: note:   __gnu_cxx::__normal_iterator<int*, std::vector<int> >& __gnu_cxx::__normal_iterator<int*, std::vector<int> >::operator=    (__gnu_cxx::__normal_iterator<int*, std::vector<int> >&&)
  /usr/include/c++/4.8/bits/stl_iterator.h:708:11: note:   no known      conversion for argument 1 f

Answer 1

您需要使用vector<int>::const_iterator代替vector<int>::iterator。

如果您使用的是支持C ++ 11或更高版本的编译器，则可以使用auto类型。

auto i = A.begin();

Answer 2

你不能使用常规迭代器来通过const向量。

vector<int>::iterator i必须为::const_iterator i。

请参阅此问题What is the difference between const_iterator and non-const iterator in the C++ STL?

Answer 3

迭代器必须是const_iterator，参数为const vector<int>

更改行

vector<int>::iterator i;

到

vector<int>::const_iterator i;

或使用auto获取类型

Answer 4

由于您将向量作为 const 传递，因此正常的迭代器无法完成工作。相反，你需要 const_iterator 来获取 const vector 。

int Solution::maxSubArray(const vector<int> &A) {
vector<int>::const_iterator i;
for(i = A.begin(); i != A.end(); ++i)
{   
 ....
}

那应该为你修好！

为什么我的矢量迭代器没有显示operator =？

4 个答案: