poj1939
简单题
![](https://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif)
#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
using namespace std;
struct Point
{
long long x, y;
}first, last, now;
int n;
void input()
{
printf("%d ", n);
scanf("%lld%lld", &first.x, &first.y);
last = first;
for (int i = 1; i < n; i++)
{
scanf("%lld%lld", &now.x, &now.y);
printf("%.6f %.6f ", (last.x + now.x) / 2.0, (now.y + last.y) / 2.0);
last = now;
}
now = first;
printf("%.6f %.6f ", (last.x + now.x) / 2.0, (now.y + last.y) / 2.0);
putchar('\n');
}
int main()
{
//freopen("t.txt", "r", stdin);
while (scanf("%d", &n) != EOF)
input();
return 0;
}