我正在尝试解决this UVa problem。C++“矢量迭代器不可递减”?
我试图用Vector来解决这个问题。我需要模拟像循环链表这样的东西,所以我使用迭代器来访问元素。但尝试之后,我发现Vector迭代器存在一些关于增量和减量的问题,并且我无法使用reverse_iterator作为参数来擦除该元素。我现在很困惑。我的代码有什么问题,因为我错过了一些重要的细节,或者我应该以另一种方式解决这个问题?
在此先感谢。
这里是我的代码
#include <iostream>
#include <vector>
#include <iomanip>
using namespace std;
vector<int> people;
int main()
{
int n, k, m; // k -> counter clockwise, m -> cloclwise
while (cin >> n >> k >> m)
{
if (n == 0 && k == 0 && m == 0)
return 0;
for (int i = 1; i <= n; i++)
people.push_back(i);
vector<int>::iterator k_pos = people.begin();
vector<int>::reverse_iterator m_pos = people.rbegin();
//cout << n << " " << k << " " << m << endl;
while (!people.empty())
{
int k_choose, m_choose;
for (int i = 1; i < k; i++)
{
k_pos++;
if (k_pos == people.end()) // if reach the end, go to begin
k_pos = people.begin();
}
k_choose = *k_pos;
cout << k_choose << endl;
for (int i = 1; i < m; i++)
{
m_pos++;
if (m_pos == people.rend())
m_pos = people.rbegin();
}
m_choose = *m_pos;
if (k_choose == m_choose)
{
cout << setw(3) << k_choose << ",";
people.erase(k_pos); // erase the element
}
else
{
cout << setw(3) << k_choose << setw(3) << m_choose << ",";
k_pos = people.erase(k_pos); // erase the element
//vector<int>::iterator temp;
//for (temp = people.begin(); *temp != *m_pos; temp++)
//{
//}
//cout << "ok" << endl;
people.erase(--m_pos.base());*****problem
}
vector<int>::iterator temp;
for (temp = people.begin(); temp != people.end(); temp++)
cout << *temp << endl;
k_pos++; *****problem
if (k_pos == people.end()) // point to next
k_pos = people.begin();
m_pos++; *****problem
if (m_pos == people.rend()) // point to next
m_pos = people.rbegin();
}
}
return 0;
}
“利用指数” 是指使用Vector的 “[]”? – iceman126 2012-02-02 19:04:40
是的。无论重新分配矢量,该运算符将始终正常工作。 – 2012-02-02 19:14:23
感谢您的回答。我会尝试的。 – iceman126 2012-02-02 19:20:14