HW18

index.php

@@ -0,0 +1,80 @@
+<?php
+
+
+class Solution
+{
+
+    /**
+     * @param Integer $numerator
+     * @param Integer $denominator
+     * @return String
+     */
+    function fractionToDecimal($numerator, $denominator)
+    {
+        if ($numerator == 0) {
+            return "0";
+        }
+
+        $result = '';
+
+        if (($numerator < 0) ^ ($denominator < 0)) {
+            $result .= '-';
+        }
+
+        $numerator = abs($numerator);
+        $denominator = abs($denominator);
+        $result .= (string)(int)($numerator / $denominator);
+
+        $remainder = $numerator % $denominator;
+        if ($remainder == 0) {
+            return $result;
+        }
+
+        $result .= '.';
+
+        $fractionalPart = [];
+        $map = [];
+
+        while ($remainder != 0) {
+            if (isset($map[$remainder])) {
+                $startIndex = $map[$remainder];
+                $nonRepeatingPart = implode('', array_slice($fractionalPart, 0, $startIndex));
+                $repeatingPart = implode('', array_slice($fractionalPart, $startIndex));
+                return $result . $nonRepeatingPart . '(' . $repeatingPart . ')';
+            }
+
+            $map[$remainder] = count($fractionalPart);
+            $remainder *= 10;
+            $fractionalPart[] = (string)(int)($remainder / $denominator);
+            $remainder %= $denominator;
+        }
+
+        return $result . implode('', $fractionalPart);
+    }
+}
+
+
+class Solution2
+{
+    /**
+     * @param ListNode $headA
+     * @param ListNode $headB
+     * @return ListNode
+     */
+    function getIntersectionNode($headA, $headB)
+    {
+        $pointerA = $headA;
+        $pointerB = $headB;
+
+        while ($pointerA !== $pointerB) {
+            $pointerA = $pointerA ? $pointerA->next : $headB;
+            $pointerB = $pointerB ? $pointerB->next : $headA;
+
+            if ($pointerA === $pointerB) {
+                return $pointerA;
+            }
+        }
+
+        return $pointerA;
+    }
+}