update ucpc2026

source/Graph/Matching.cpp

@@ -1,18 +1,15 @@
-// From https://github.com/koosaga/olympiad
-// matching_short.cpp
-const int MAXN = 2020 + 1;
-// 1-based Vertex index
-int vis[MAXN], par[MAXN], orig[MAXN], match[MAXN], aux[MAXN], t, N;
-vector<int> conn[MAXN];
-queue<int> Q;
+// Originate from https://github.com/koosaga/olympiad
+// matching_short.cpp / 1-based Vertex index / const int N = 2020 + 1;
+int vis[N], par[N], orig[N], match[N], aux[N], t, n;
+vector<int> conn[N]; queue<int> Q;
+
 void addEdge(int u, int v) { conn[u].push_back(v); conn[v].push_back(u); }
 void init(int n) {
-	N = n; t = 0;
-	for(int i=0; i<=n; ++i) {
-		conn[i].clear();
-		match[i] = aux[i] = par[i] = 0;
-	}
+	::n = n; t = 0;
+	fors(i, 0, n) conn[i].clear();
+	fors(i, 0, n) match[i] = aux[i] = par[i] = 0;
 }
+
 void augment(int u, int v) {
 	int pv = v, nv;
 	do {
@@ -35,12 +32,11 @@ void blossom(int v, int w, int a) {
 	while(orig[v] != a) {
 		par[v] = w; w = match[v];
 		if(vis[w] == 1) Q.push(w), vis[w] = 0;
-		orig[v] = orig[w] = a;
-		v = par[w];
+		orig[v] = orig[w] = a; v = par[w];
 	}
 }
 bool bfs(int u) {
-	fill(vis+1, vis+1+N, -1); iota(orig + 1, orig + N + 1, 1);
+	fill(vis+1, vis+1+n, -1); iota(orig + 1, orig + n + 1, 1);
 	Q = queue<int> (); Q.push(u); vis[u] = 0;
 	while(!Q.empty()) {
 		int v = Q.front(); Q.pop();
@@ -58,17 +54,15 @@ bool bfs(int u) {
 	}
 	return false;
 }
-int Match() {
+int matching() {
 	int ans = 0;
 	// find random matching (not necessary, constant improvement)
-	vector<int> V(N-1); iota(V.begin(), V.end(), 1);
+	vector<int> V(n-1); iota(V.begin(), V.end(), 1);
 	shuffle(V.begin(), V.end(), mt19937(0x94949));
-	for(auto x: V) if(!match[x]){
-		for(auto y: conn[x]) if(!match[y]) {
-			match[x] = y, match[y] = x;
-			++ans; break;
-		}
+	for(auto x: V) if(!match[x]) for(auto y: conn[x]) if(!match[y]) {
+		match[x] = y, match[y] = x;
+		++ans; break;
 	}
-	for(int i=1; i<=N; ++i) if(!match[i] && bfs(i)) ++ans;
+	forr(i, n) if(!match[i] && bfs(i)) ++ans;
 	return ans;
 }