From 5ac2496d1d15237ce0eec3128e357a8dcb02d119 Mon Sep 17 00:00:00 2001
From: Bruno Freitas Tissei <bft15@inf.ufpr.br>
Date: Wed, 16 May 2018 14:04:53 +0200
Subject: [PATCH] Add bipartite matching
Signed-off-by: Bruno Freitas Tissei <bft15@inf.ufpr.br>
---
graph/bipartite_match.cpp | 38 ++++++++++++++++++++++++++++++++++++++
1 file changed, 38 insertions(+)
create mode 100644 graph/bipartite_match.cpp
diff --git a/graph/bipartite_match.cpp b/graph/bipartite_match.cpp
new file mode 100644
index 0000000..335b4d0
--- /dev/null
+++ b/graph/bipartite_match.cpp
@@ -0,0 +1,38 @@
+/**
+ * Bipartite Matching (simplified Ford-Fulkerson)
+ *
+ * Complexity (Time): O(n + m)
+ * Complexity (Space): O(n + m)
+ */
+
+vector<int> graph[MAX];
+int cont[MAX], match[MAX];
+
+// Find match for x
+int dfs(int x) {
+ if (cont[x])
+ return 0;
+
+ cont[x] = 1;
+ for (auto i : graph[x])
+ if (match[i] == -1 || dfs(match[v])) {
+ match[i] = x;
+ return 1;
+ }
+
+ return 0;
+}
+
+// Return number of left elements in matching and fills match array with the
+// match itself (match[right_i] = left_i)
+int bipartite_matching(int n) {
+ int ans = 0;
+ memset(match, -1, sizeof match);
+
+ for (int i = 0; i < n; ++i) {
+ memset(cont, 0, sizeof cont);
+ ans += dfs(i);
+ }
+
+ return ans;
+}
--
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