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103 | #include <bits/stdc++.h>
using namespace std;
namespace IO
{
#define siz 1 << 20
char buf[siz], *pa = buf, *pb = buf;
#define gc() \
(pa == pb && (pb = (pa = buf) + fread(buf, 1, siz, stdin), pa == pb)) \
? EOF \
: *(pa++)
inline int read()
{
int x = 0, f = 1;
char ch;
for (ch = gc(); !isdigit(ch); ch = gc())
if (ch == '-') f = -1;
for (; isdigit(ch); ch = gc())
{
x = (x << 3) + (x << 1) + (ch - '0');
}
return f * x;
}
inline void write(int x)
{
if (x < 0)
{
putchar('-');
x = -x;
}
if (x > 9) write(x / 10);
putchar(x % 10 + '0');
return;
}
#undef siz
#undef gc
} // namespace IO
using IO::read;
using IO::write;
#define truep(x) (x)
#define falsep(x) ((x) + n)
#define MAXN 1000010 << 1
#define MAXM 1000010 << 1
vector<int> e[MAXN];
stack<int> s;
queue<int> q;
int n, m, color[MAXN], idx, cnt, ind[MAXN], low[MAXN], dfn[MAXN];
bool book[MAXN];
void dfs(int u)
{
dfn[u] = low[u] = ++idx;
s.push(u), book[u] = true;
for (int i = 0; i < e[u].size(); i++)
{
int v = e[u][i];
if (!dfn[v])
{
dfs(v);
low[u] = min(low[u], low[v]);
}
else if (book[v])
low[u] = min(low[u], dfn[v]);
}
if (low[u] == dfn[u])
{
cnt++;
int t;
do
{
t = s.top();
s.pop();
color[t] = cnt;
book[t] = false;
} while (t != u);
}
}
int main()
{
n = read(), m = read();
for (int i = 1; i <= m; i++)
{
int u = read(), a = read(), v = read(), b = read();
e[truep(u) * a + falsep(u) * (a ^ 1)].push_back(truep(v) * (b ^ 1) +
falsep(v) * b);
e[truep(v) * b + falsep(v) * (b ^ 1)].push_back(truep(u) * (a ^ 1) +
falsep(u) * a);
}
for (int i = 1; i <= (n << 1); i++)
if (!dfn[i]) dfs(i);
for (int i = 1; i <= n; i++)
{
if (color[truep(i)] == color[falsep(i)])
{
puts("IMPOSSIBLE");
return 0;
}
}
puts("POSSIBLE");
for (int i = 1; i <= n; i++)
{
write(color[truep(i)] > color[falsep(i)]), putchar(' ');
}
return 0;
}
|