#include <iostream>
#include <string.h>
using namespace std;
int a[12];
bool used[12] = {};
int main()
{
while (cin >> a[0])
{
for (int i = 1; i < 12; i++)
cin >> a[i];
for (int i = 0; i < 12; i += 2)
{
if (a[i] < a[i + 1])
{
int t = a[i + 1];
a[i + 1] = a[i];
a[i] = t;
}
}
int sum1 = 0;
memset(used, false, sizeof(used));
for (int i = 0; i < 12; i += 2)
{
int sum = 1;
for (int j = i + 2; j < 12; j += 2)
{
if (used[j])
continue;
if (a[i] == a[j] && a[i + 1] == a[j + 1])
{
sum += 1;
used[j] = true;
}
}
sum1 += sum / 2;
}
if (sum1 != 3)
{
cout << "IMPOSSIBLE" << endl;
}
else
{
int sum2 = 0;
memset(used, false, sizeof(used));
{
for (int i = 0; i < 12; i++)
{
int sum = 1;
for (int j = i + 1; j < 12; j++)
{
if (used[j])
continue;
if (a[j] == a[i])
{
used[j] = true;
sum++;
}
}
sum2 += sum / 4;
}
}
if (sum2 == 3)
cout << "POSSIBLE" << endl;
else
cout << "IMPOSSIBLE" << endl;
}
}
return 0;
}
UVa1587 - Box
最新推荐文章于 2025-04-26 23:01:23 发布