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| #include <cstdio>
#include <queue>
using namespace std;
const int N = 1e3 + 10, M = 1e5 + 10;
queue<int> q;
int stmp, vis[N];
int n, m, c[N], f[N], p[N], match[N];
int idx, hd[N], nxt[M], edg[M];
int fa(int x)
{
return p[x] == x ? x : p[x] = fa(p[x]);
}
int LCA(int x, int y)
{
stmp++;
while (true)
{
if (!x)
{
swap(x, y);
continue;
}
x = fa(x);
if (vis[x] == stmp)
return x;
vis[x] = stmp;
x = f[match[x]];
swap(x, y);
}
}
void blossom(int x, int y, int lca)
{
while (fa(x) != lca)
{
f[x] = y, y = match[x];
if (c[y] == 2)
{
c[y] = 1;
q.push(y);
}
if (fa(x) == x)
p[x] = lca;
if (fa(y) == y)
p[y] = lca;
x = f[y];
}
}
bool bfs(int st)
{
for (int i = 1; i <= n; i++)
c[i] = f[i] = 0, p[i] = i;
while (!q.empty())
q.pop();
q.push(st);
c[st] = 1;
while (!q.empty())
{
int t = q.front();
q.pop();
for (int i = hd[t]; ~i; i = nxt[i])
{
if (fa(t) == fa(edg[i]) || c[edg[i]] == 2)
continue;
if (!c[edg[i]])
{
c[edg[i]] = 2;
f[edg[i]] = t;
if (!match[edg[i]])
{
for (int j = edg[i], x; j; j = x)
{
x = match[f[j]];
match[j] = f[j];
match[f[j]] = j;
}
return true;
}
else
{
c[match[edg[i]]] = 1;
q.push(match[edg[i]]);
}
}
else
{
int lca = LCA(t, edg[i]);
blossom(t, edg[i], lca);
blossom(edg[i], t, lca);
}
}
}
return false;
}
void add(int a, int b)
{
nxt[++idx] = hd[a];
hd[a] = idx;
edg[idx] = b;
}
int main()
{
scanf("%d%d", &n, &m);
for (int i = 1; i <= n; i++)
hd[i] = -1;
for (int u, v; m; m--)
{
scanf("%d%d", &u, &v);
add(u, v);
add(v, u);
}
int res = 0;
for (int i = 1; i <= n; i++)
if (!match[i])
res += bfs(i);
printf("%d\n", res);
for (int i = 1; i <= n; i++)
printf("%d ", match[i]);
return 0;
}
|