Question

我有以下程序，程序的目的是显示列表向量中每个值的发生次数。

如果元组2：3在向量中出现3次，则程序会将此显示给用户。

预期输出

0：8发生1次％x
2：3发生3次％x
9：5发生2次％x
8：9发生1次％x

实际输出：

2：3发生3次％42
8：9发生1次％14
9：5发生3次％42

知道我做错了什么吗？这是我正在使用的代码的完整且可验证的工作版本

非常感谢任何帮助。

#include <vector>
    #include <iostream>
    #include <tuple>

    using namespace std;
    int counter = 0;
    double percentage;
    int val = 0;
    vector<tuple<int, int>> list = { make_tuple(2, 3), make_tuple(0, 8), make_tuple(2, 3), make_tuple(8, 9), make_tuple(9, 5), make_tuple(9, 5), make_tuple(2, 3) };


         int binarysearch(vector<tuple<int, int>> list, int low, int high, tuple<int, int> number)
         {
            int index = low;
            int mid = 0;
            // loop till the condition is true
            while (low <= high) {
                // divide the array for search
                mid = (low + high) / 2;

                if (list.at(mid) > number) {
                    high = mid - 1;

                }
                else {
                    low = mid + 1;
                }

            }return (high - index + 1);

        }

         int main()
         {

             while (counter <= list.size() - 1) {

                 val = binarysearch(list, counter, list.size() - 1, list.at(counter));
                 percentage = val * 100 / list.size();
                 cout << "Value: " << get<0>(list.at(counter)) << ":" << get<1>(list.at(counter)) << " Occurs: " << val << " Time(s)" << " %" << percentage << endl;
                 counter += val;
             }



             return 0;
         }

Answer 1

您无法在未排序的容器上运行二进制搜索。二进制搜索依赖于以下事实：如果中点不是您想要的元素，那么如果它超过中点，则所需的元素将位于上半部分，如果中间点更小，则将位于下半部分。您无法保证使用未分类的容器。

现在不是编写自己的函数来获取每次出现的次数，而是可以使用<span ng-bind-html="friend.name | customFilter"></span> <span>{{friend.phone}}</span>为你做这样的事情

std::map

哪个输出：

std::vector<std::tuple<int, int>> list = { make_tuple(2, 3), make_tuple(0, 8), make_tuple(2, 3), make_tuple(8, 9), make_tuple(9, 5), make_tuple(9, 5), make_tuple(2, 3) };
std::map<std::tuple<int, int>, int> occurrences;
for (const auto& e : list) // go though the vector and add to the map.  increment the value on duplication
    ++occurrences[e];

for (const auto& e : occurrences)
{
    double percentage = e.second * 100 / list.size();
    cout << "Value: " << get<0>(e.first) << ":" << get<1>(e.first) << " Occurs: " << e.second << " Time(s)" << " %" << percentage << endl;
}

没有找到预期的事件

1 个答案: