(attempt) 2.7

Author: Tony K Tan

lib/chapter2/2.7 - Intersection/intersection.js

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+var LinkedList = require('./../util/LinkedList');
+
+var peek = function(stack) {
+  return stack[stack.length - 1];
+};
+
+var intersection = function(head1, head2) {
+  var stack1 = [];
+  var stack2 = [];
+  
+  while (head1 !== null) {
+    stack1.push(head1);
+    head1 = head1.next;
+  }
+
+  while (head2 !== null) {
+    stack2.push(head2);
+    head2 = head2.next;
+  }
+
+  // if not intersecting return undefined.
+  if (stack1.length === 0 || stack2.length === 0) {
+    return undefined;
+  } else if (peek(stack1) !== peek(stack2)) {
+    return undefined;
+  } else {
+    var intersect;
+    while (peek(stack1) === peek(stack2)) {
+      intersect = peek(stack1);
+      stack1.pop();
+      stack2.pop();
+    }
+    return intersect;
+  }
+  // if intersecting, return intersecting node.
+};
+
+/* TEST */
+
+var a = new LinkedList('a');
+var b = new LinkedList('b');
+var c = new LinkedList('c');
+var d = new LinkedList('d');
+var e = new LinkedList('e');
+var f = new LinkedList('f');
+var g = new LinkedList('g');
+var h = new LinkedList('h');
+
+a.next = b;
+b.next = c;
+c.next = d;
+d.next = e;
+e.next = f;
+f.next = g;
+g.next = h;
+
+var a1 = new LinkedList('a1');
+var b1 = new LinkedList('b1');
+var c1 = new LinkedList('c1');
+
+a1.next = b1;
+b1.next = c1;
+c1.next = d;
+
+var intersectNode = intersection(a, a1);
+
+console.log(intersectNode.value);

lib/chapter2/util/LinkedList.js

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+module.exports = function(value) {
+  this.value = value;
+  this.next = null;
+};

lib/chapter2/util/printList.js

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+module.exports = function(head) {
+  while (head !== null) {
+    console.log(head.value);
+    head = head.next;
+  }
+};