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48 lines
1.3 KiB
Java
48 lines
1.3 KiB
Java
import java.util.*;
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public class MinCostFlowSimple {
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public static int[] minCostFlow(int[][] cap, int[][] cost, int s, int t) {
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int n = cap.length;
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int[] d = new int[n];
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int[] p = new int[n];
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for (int flow = 0, flowCost = 0;; ++flow) {
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Arrays.fill(d, Integer.MAX_VALUE);
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d[s] = 0;
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for (int i = 0; i < n - 1; i++)
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for (int j = 0; j < n; j++)
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for (int k = 0; k < n; k++)
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if (cap[j][k] > 0 && d[j] < Integer.MAX_VALUE && d[k] > d[j] + cost[j][k]) {
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d[k] = d[j] + cost[j][k];
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p[k] = j;
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}
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if (d[t] == Integer.MAX_VALUE)
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return new int[] { flowCost, flow };
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flowCost += d[t];
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for (int v = t; v != s; v = p[v]) {
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--cap[p[v]][v];
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++cap[v][p[v]];
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}
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}
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}
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public static void addEdge(int[][] cap, int[][] cost, int u, int v, int edgeCapacity, int edgeCost) {
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cap[u][v] = edgeCapacity;
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cost[u][v] = edgeCost;
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cost[v][u] = -edgeCost;
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}
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// Usage example
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public static void main(String[] args) {
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int n = 3;
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int[][] capacity = new int[n][n];
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int[][] cost = new int[n][n];
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addEdge(capacity, cost, 0, 1, 3, 1);
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addEdge(capacity, cost, 0, 2, 2, 1);
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addEdge(capacity, cost, 1, 2, 2, 1);
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int[] costFlow = minCostFlow(capacity, cost, 0, 2);
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System.out.println(6 == costFlow[0]);
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System.out.println(4 == costFlow[1]);
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}
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}
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