https://codeforces.com/contest/71/problem/C
这道题，比较难，现在还没有完全吃透，参考别人的代码，大概意思
1）将圆桌n个骑士，分成 i (>3) 部分，每一份 step 个骑士。
2）然后每一部分执行step步，寻找是否=0，如果最后一个是0，那么结果就是0
注意：代码还没有完全理解，我参考别人的代码，理解到这里，还是不完全理解，暂时存放这里，方便手机查看和再思考。
C. Round Table Knights
代码
分析代码
#include <iostream>
using namespace std;
int main()
{
int n;
bool mood_good = true;
int step = 0;
int *list;
cin >> n;
list=new int[n];
for (int i = 0; i < n; i++)
{
cin >> list[i];
}
for (int i = 3; i <= n; i++)
{
//You must make N elements split i equally into parts. 将元素分i份。
if (n % i == 0)
{
//cout << "n%i= "<<n<<" % "<<i<<" = "<< n%i << endl;
step = n / i;//每一份step个
//cout <<"i="<< i << ",step= " << step << endl;
//every part: to check
for (int start = 0; start < step; start++)
{ //然后在每份的元素里操作
mood_good = true;
//cout << "start=" << start << endl;
// i is i parts
//这里是每份的元素。
for (int k = 0; k < i; k++)
{
int pos = start + k * step;
//cout << "list[pos("<<pos<<")]=" << list[pos] << endl;
if (pos >= n)
{
pos -= n;
//cout << "restart begin pos=" << pos << endl;
}
if (1!=list[pos])
{
//cout << "bad" << endl;
mood_good = false;
}
}
if (true == mood_good)
{
cout <<"YES"<<endl;
i = n + 10000; //to exit
break;
}
}
}
}
if (mood_good == false)
{
cout << "NO" << endl;
}
delete[] list;
return 0;
}
cpp
/*
ref code:DhvanitVaghani
#include <iostream>
using namespace std;
int main() {
int n;
cin >> n;
int a[n];
for (int i = 0; i < n; i++) cin >> a[i];
for (int d = 3; d <= n; d++) {
if (n % d == 0) {
int step = n / d;
for (int start = 0; start < step; start++) {
bool ok = true;
for (int i = 0; i < d; i++) {
int pos = start + i * step;
if (pos >= n) pos -= n;
if (a[pos] != 1) ok = false;
}
if (ok) {
cout << "YES\n";
return 0;
}
}
}
}
cout << "NO\n";
return 0;
}
*/
#include <iostream>
using namespace std;
int main()
{
int n;
bool mood_good = true;
int step = 0;
int *list;
cin >> n;
list=new int[n];
for (int i = 0; i < n; i++)
{
cin >> list[i];
}
for (int i = 3; i <= n; i++)
{
//You must make N elements split i equally into parts.
if (n % i == 0)
{
//cout << "n%i= "<<n<<" % "<<i<<" = "<< n%i << endl;
step = n / i;
//cout <<"i="<< i << ",step= " << step << endl;
//every part: to check
for (int start = 0; start < step; start++)
{
mood_good = true;
//cout << "start=" << start << endl;
// i is i parts
for (int k = 0; k < i; k++)
{
int pos = start + k * step;
//cout << "list[pos("<<pos<<")]=" << list[pos] << endl;
if (pos >= n)
{
pos -= n;
//cout << "restart begin pos=" << pos << endl;
}
if (1!=list[pos])
{
//cout << "bad" << endl;
mood_good = false;
}
}
if (true == mood_good)
{
cout <<"YES"<<endl;
i = n + 10000; //to exit
break;
}
}
}
}
if (mood_good == false)
{
cout << "NO" << endl;
}
delete[] list;
return 0;
}
/*
Examples
InputCopy
3
1 1 1
OutputCopy
YES
InputCopy
6
1 0 1 1 1 0
OutputCopy
YES
InputCopy
6
1 0 0 1 0 1
OutputCopy
NO
*/