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| 1 | +class Bucket { |
| 2 | + var $leftClose; |
| 3 | + var $rightOpen; |
| 4 | + var $usedFlag; |
| 5 | + |
| 6 | + function __construct() { |
| 7 | + $this->leftClose = 0; |
| 8 | + $this->rightOpen = 0; |
| 9 | + $this->usedFlag = false; |
| 10 | + } |
| 11 | +} |
| 12 | + |
| 13 | +class Solution { |
| 14 | + |
| 15 | + /** |
| 16 | + * @param Integer[] $nums |
| 17 | + * @return Integer |
| 18 | + */ |
| 19 | + function maximumGap($nums) { |
| 20 | + if ($nums==null || count($nums)<2) { |
| 21 | + return 0; |
| 22 | + } |
| 23 | + |
| 24 | + // find the maximum value and the minimum value in array |
| 25 | + $max = $nums[0]; |
| 26 | + $min = $nums[0]; |
| 27 | + foreach ($nums as $num) { |
| 28 | + $max = $max<$num ? $num : $max; |
| 29 | + $min = $min>$num ? $num : $min; |
| 30 | + } |
| 31 | + |
| 32 | + // the size of bucket must > 1 |
| 33 | + $bucketSize = intval(max(1, ($max - $min) / (count($nums) - 1))); |
| 34 | + $bucketNum = intval(($max-$min) / $bucketSize + 1); |
| 35 | + |
| 36 | + $buckets = array_fill(0, $bucketNum, null); |
| 37 | + for ($i=0; $i<count($buckets); $i++) { |
| 38 | + $buckets[$i] = new Bucket(); |
| 39 | + } |
| 40 | + |
| 41 | + // locating correct bucket |
| 42 | + foreach ($nums as $num) { |
| 43 | + $bucketIndex = intval(($num - $min) / $bucketSize); |
| 44 | + |
| 45 | + if ($buckets[$bucketIndex]->usedFlag == false) { |
| 46 | + $buckets[$bucketIndex]->leftClose = $num; |
| 47 | + $buckets[$bucketIndex]->rightOpen = $num; |
| 48 | + $buckets[$bucketIndex]->usedFlag = true; |
| 49 | + } else { |
| 50 | + $buckets[$bucketIndex]->leftClose = min($num, $buckets[$bucketIndex]->leftClose); |
| 51 | + $buckets[$bucketIndex]->rightOpen = max($num, $buckets[$bucketIndex]->rightOpen); |
| 52 | + } |
| 53 | + } |
| 54 | + |
| 55 | + $maxGap = 0; |
| 56 | + $preRightOpen = $buckets[0]->rightOpen; |
| 57 | + for ($i=1; $i<count($buckets); $i++) { |
| 58 | + if ($buckets[$i]->usedFlag == false) { |
| 59 | + continue; |
| 60 | + } |
| 61 | + $maxGap = max($maxGap, $buckets[$i]->leftClose-$preRightOpen); |
| 62 | + $preRightOpen = $buckets[$i]->rightOpen; |
| 63 | + } |
| 64 | + |
| 65 | + return $maxGap; |
| 66 | + } |
| 67 | +} |
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