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    <p>Here is the another version of Jessup's code. I simply add some other functions and now the code calculates earliest/latest start and finish times, slack and whether the node is on the critical path or not. (I simply added the functions and get the result, I haven't put much effort on algorithm and coding)</p> <pre><code>public class CriticalPath { public static int maxCost; public static String format = "%1$-10s %2$-5s %3$-5s %4$-5s %5$-5s %6$-5s %7$-10s\n"; public static void main(String[] args) { // The example dependency graph HashSet&lt;Task&gt; allTasks = new HashSet&lt;Task&gt;(); Task end = new Task("End", 0); Task F = new Task("F", 2, end); Task A = new Task("A", 3, end); Task X = new Task("X", 4, F, A); Task Q = new Task("Q", 2, A, X); Task start = new Task("Start", 0, Q); allTasks.add(end); allTasks.add(F); allTasks.add(A); allTasks.add(X); allTasks.add(Q); allTasks.add(start); Task[] result = criticalPath(allTasks); print(result); // System.out.println("Critical Path: " + Arrays.toString(result)); } // A wrapper class to hold the tasks during the calculation public static class Task { // the actual cost of the task public int cost; // the cost of the task along the critical path public int criticalCost; // a name for the task for printing public String name; // the earliest start public int earlyStart; // the earliest finish public int earlyFinish; // the latest start public int latestStart; // the latest finish public int latestFinish; // the tasks on which this task is dependant public HashSet&lt;Task&gt; dependencies = new HashSet&lt;Task&gt;(); public Task(String name, int cost, Task... dependencies) { this.name = name; this.cost = cost; for (Task t : dependencies) { this.dependencies.add(t); } this.earlyFinish = -1; } public void setLatest() { latestStart = maxCost - criticalCost; latestFinish = latestStart + cost; } public String[] toStringArray() { String criticalCond = earlyStart == latestStart ? "Yes" : "No"; String[] toString = { name, earlyStart + "", earlyFinish + "", latestStart + "", latestFinish + "", latestStart - earlyStart + "", criticalCond }; return toString; } public boolean isDependent(Task t) { // is t a direct dependency? if (dependencies.contains(t)) { return true; } // is t an indirect dependency for (Task dep : dependencies) { if (dep.isDependent(t)) { return true; } } return false; } } public static Task[] criticalPath(Set&lt;Task&gt; tasks) { // tasks whose critical cost has been calculated HashSet&lt;Task&gt; completed = new HashSet&lt;Task&gt;(); // tasks whose critical cost needs to be calculated HashSet&lt;Task&gt; remaining = new HashSet&lt;Task&gt;(tasks); // Backflow algorithm // while there are tasks whose critical cost isn't calculated. while (!remaining.isEmpty()) { boolean progress = false; // find a new task to calculate for (Iterator&lt;Task&gt; it = remaining.iterator(); it.hasNext();) { Task task = it.next(); if (completed.containsAll(task.dependencies)) { // all dependencies calculated, critical cost is max // dependency // critical cost, plus our cost int critical = 0; for (Task t : task.dependencies) { if (t.criticalCost &gt; critical) { critical = t.criticalCost; } } task.criticalCost = critical + task.cost; // set task as calculated an remove completed.add(task); it.remove(); // note we are making progress progress = true; } } // If we haven't made any progress then a cycle must exist in // the graph and we wont be able to calculate the critical path if (!progress) throw new RuntimeException("Cyclic dependency, algorithm stopped!"); } // get the cost maxCost(tasks); HashSet&lt;Task&gt; initialNodes = initials(tasks); calculateEarly(initialNodes); // get the tasks Task[] ret = completed.toArray(new Task[0]); // create a priority list Arrays.sort(ret, new Comparator&lt;Task&gt;() { @Override public int compare(Task o1, Task o2) { return o1.name.compareTo(o2.name); } }); return ret; } public static void calculateEarly(HashSet&lt;Task&gt; initials) { for (Task initial : initials) { initial.earlyStart = 0; initial.earlyFinish = initial.cost; setEarly(initial); } } public static void setEarly(Task initial) { int completionTime = initial.earlyFinish; for (Task t : initial.dependencies) { if (completionTime &gt;= t.earlyStart) { t.earlyStart = completionTime; t.earlyFinish = completionTime + t.cost; } setEarly(t); } } public static HashSet&lt;Task&gt; initials(Set&lt;Task&gt; tasks) { HashSet&lt;Task&gt; remaining = new HashSet&lt;Task&gt;(tasks); for (Task t : tasks) { for (Task td : t.dependencies) { remaining.remove(td); } } System.out.print("Initial nodes: "); for (Task t : remaining) System.out.print(t.name + " "); System.out.print("\n\n"); return remaining; } public static void maxCost(Set&lt;Task&gt; tasks) { int max = -1; for (Task t : tasks) { if (t.criticalCost &gt; max) max = t.criticalCost; } maxCost = max; System.out.println("Critical path length (cost): " + maxCost); for (Task t : tasks) { t.setLatest(); } } public static void print(Task[] tasks) { System.out.format(format, "Task", "ES", "EF", "LS", "LF", "Slack", "Critical?"); for (Task t : tasks) System.out.format(format, (Object[]) t.toStringArray()); } } </code></pre>
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