blob: 5e2314f7c2e2e64c5243982cda6d93886d5eb4c6 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
|
// Laufzeit: O(n*min(ans^2, |E|))
vector<vector<int>> adjlist; // Von links nach rechts.
vector<int> pairs; // Der gematchte Knoten oder -1.
vector<bool> visited;
bool dfs(int v) {
if (visited[v]) return false;
visited[v] = true;
for (auto w : adjlist[v]) if (pairs[w] < 0 || dfs(pairs[w])) {
pairs[w] = v; pairs[v] = w; return true;
}
return false;
}
int kuhn(int n) { // n = #Knoten links.
pairs.assign(NUM_VERTICES, -1);
int ans = 0;
// Greedy Matching. Optionale Beschleunigung.
for (int i = 0; i < n; i++) for (auto w : adjlist[i])
if (pairs[w] == -1) { pairs[i] = w; pairs[w] = i; ans++; break; }
for (int i = 0; i < n; i++) if (pairs[i] == -1) {
visited.assign(n, false);
ans += dfs(i);
}
return ans; // Größe des Matchings.
}
|
