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MaxFlow.java
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MaxFlow.java
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/*
* Copyright 2020 Emory University
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package edu.emory.cs.graph.flow;
import edu.emory.cs.graph.Edge;
import edu.emory.cs.graph.Graph;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
/**
* @author Jinho D. Choi ({@code jinho.choi@emory.edu})
*/
public class MaxFlow {
private Map<Edge, Double> flow_map;
private double maxflow;
public MaxFlow(Graph graph) {
init(graph);
}
public void init(Graph graph) {
flow_map = new HashMap<>();
maxflow = 0;
for (Edge edge : graph.getAllEdges())
flow_map.put(edge, 0d);
}
// ============================== Getters ==============================
public double getMaxFlow() {
return maxflow;
}
public double getResidual(Edge edge) {
return edge.getWeight() - flow_map.get(edge);
}
// ============================== Setters ==============================
public void updateFlow(List<Edge> path, double flow) {
path.forEach(e -> updateFlow(e, flow));
maxflow += flow;
}
public void updateFlow(Edge edge, double flow) {
Double prev = flow_map.getOrDefault(edge, 0d);
flow_map.put(edge, prev + flow);
}
}