boj 6086 최대 유량

Author: emost22

network flow/6086.cpp

@@ -0,0 +1,79 @@
+#include <iostream>
+#include <vector>
+#include <queue>
+#include <algorithm>
+#define MAX 52
+#define INF 1000000000
+using namespace std;
+
+vector<int> a[MAX];
+bool visit[MAX][MAX];
+int c[MAX][MAX], f[MAX][MAX], d[MAX];
+int N, result, w;
+char u, v;
+
+char alpha(char x) {
+	if (x < 97) return x - 65;
+	else return x - 71;
+}
+
+void maxflow(int s, int e) {
+	while (1) {
+		fill(d, d + MAX, -1);
+		queue<int> q;
+		q.push(s);
+		while (!q.empty()) {
+			int x = q.front();
+			q.pop();
+
+			for (int i = 0; i < a[x].size(); i++) {
+				int y = a[x][i];
+
+				if (c[x][y] - f[x][y] > 0 && d[y] == -1) {
+					q.push(y);
+					d[y] = x;
+					if (y == e) break;
+				}
+			}
+		}
+		if (d[e] == -1) break;
+		int flow = INF;
+
+		for (int i = e; i != s; i = d[i]) {
+			flow = min(flow, c[d[i]][i] - f[d[i]][i]);
+		}
+
+		for (int i = e; i != s; i = d[i]) {
+			f[d[i]][i] += flow;
+			f[i][d[i]] -= flow;
+		}
+
+		result += flow;
+	}
+}
+
+int main() {
+	cin.tie(NULL); cout.tie(NULL);
+	ios::sync_with_stdio(false);
+
+	cin >> N;
+	for (int i = 0; i < N; i++) {
+		cin >> u >> v >> w;
+		u = alpha(u);
+		v = alpha(v);
+		if (!visit[u][v]) {
+			a[u].push_back(v);
+			a[v].push_back(u);
+			visit[u][v] = true;
+			visit[v][u] = true;
+		}
+		c[u][v] += w;
+		c[v][u] += w;
+	}
+
+	maxflow(0, 25);
+
+	cout << result << '\n';
+
+	return 0;
+}