95 lines
2 KiB
Java
95 lines
2 KiB
Java
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class RunnyStack<Base> {
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class Run {
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public Base object;
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public int length;
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public Run next;
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public Run(Base object, Run next) {
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this.object = object;
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this.length = 1;
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this.next = next;
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}
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public Run(Base object) {
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this(object, null);
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}
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public boolean is(Base other) {
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if (other == null || this.object == null) {
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return this.object == other;
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} else {
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return this.object.equals(other);
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}
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}
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}
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private int runs, depth;
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private Run top;
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public RunnyStack() {
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this.runs = 0;
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this.depth = 0;
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this.top = null;
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}
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public boolean isEmpty() {
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return this.top == null;
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}
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public int depth() {
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return this.depth;
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}
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public int runs() {
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return this.runs;
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}
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public void push(Base object) {
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Run run = new Run(object, top);
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if (this.top == null) {
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this.runs = 1;
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this.depth = 1;
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this.top = run;
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} else {
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if (this.top.is(object)) {
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this.depth += 1;
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this.top.length += 1;
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} else {
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this.runs += 1;
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this.depth += 1;
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Run top = this.top;
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run.next = top;
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this.top = run;
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}
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}
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}
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public void pop() {
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if (this.isEmpty()) {
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throw new IllegalStateException("The stack is empty.");
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}
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this.depth -= 1;
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this.top.length -= 1;
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if (this.top.length == 0) {
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this.runs -= 1;
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this.top = this.top.next;
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}
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}
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public Base peek() {
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if (this.isEmpty()) {
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throw new IllegalStateException("The stack is empty.");
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}
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return this.top.object;
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}
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}
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class RunnyDriver {
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public static void main(String[] args) {
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RunnyStack<String> s = new RunnyStack<String>();
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s.push("A");
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System.out.println(s.peek() + " " + s.depth() + " " + s.runs()); // A 1 1
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s.push("B");
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System.out.println(s.peek() + " " + s.depth() + " " + s.runs()); // B 2 2
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s.push("B");
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System.out.println(s.peek() + " " + s.depth() + " " + s.runs()); // B 3 2
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s.pop();
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System.out.println(s.peek() + " " + s.depth() + " " + s.runs()); // B 2 2
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s.pop();
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System.out.println(s.peek() + " " + s.depth() + " " + s.runs()); // A 1 1
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}
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}
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