更新时间:2022-11-13 22:03:34
因为你包括向量,为什么不替换 int * b = new int [ n];
with std :: vector< int> b(n)
?这也照顾释放记忆,你忘了 delete [] b
。
Since you are including vector anway, why not replace int *b=new int [n];
with std::vector<int> b(n)
? This also takes care of releasing the memory, you forgot to delete[] b
.
但正如其他人所说,如果数组包含大于n的元素,您的解决方案将中断。一个更好的方法可能是使用映射到int来计数元素。这样,你也可以计算不能用作数组索引的元素,例如字符串。
But as others have mentioned, your solution will break if the array contains elements larger than n. A better approach might be to count the elements with a mapping to int. That way, you can also count elements that cannot be used as an array index, for example strings.
也没有理由限制数组。这里是一个通用的解决方案,适用于任何小于可比较的元素类型的任何容器:
There is also no reason to limit ourselves to arrays. Here is a generic solution that works with any container of any less-than comparable element type:
#include <algorithm>
#include <iterator>
#include <map>
struct by_second
{
template <typename Pair>
bool operator()(const Pair& a, const Pair& b)
{
return a.second < b.second;
}
};
template <typename Fwd>
typename std::map<typename std::iterator_traits<Fwd>::value_type, int>::value_type
most_frequent_element(Fwd begin, Fwd end)
{
std::map<typename std::iterator_traits<Fwd>::value_type, int> count;
for (Fwd it = begin; it != end; ++it)
++count[*it];
return *std::max_element(count.begin(), count.end(), by_second());
}
#include <iostream>
#include <vector>
int main()
{
std::vector<int> test {1, 2, 3, 4, 4, 4, 5};
std::pair<int, int> x = most_frequent_element(test.begin(), test.end());
std::cout << x.first << " occured " << x.second << " times";
}