solve 217 with O(n)

Author: illuz

solutions/220.Contains_Duplicate_III/AC_bucket_n.java

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+/*
+*  Author:      illuz <iilluzen[at]gmail.com>
+*  File:        AC_bucket_n.java
+*  Create Date: 2015-07-16 10:57:54
+*  Descripton:  Description see https://leetcode.com/discuss/38206/ac-o-n-solution-in-java-using-buckets-with-explanation
+*/
+
+ public class Solution {
+     public boolean containsNearbyAlmostDuplicate(int[] nums, int k, int t) {
+         if (k < 1 || t < 0) return false;
+         Map<Long, Long> map = new HashMap<>();
+         for (int i = 0; i < nums.length; i++) {
+             long remappedNum = (long) nums[i] - Integer.MIN_VALUE;
+             long bucket = remappedNum / ((long) t + 1);
+             if (map.containsKey(bucket)
+                     || (map.containsKey(bucket - 1) && remappedNum - map.get(bucket - 1) <= t)
+                     || (map.containsKey(bucket + 1) && map.get(bucket + 1) - remappedNum <= t))
+                 return true;
+             if (map.entrySet().size() >= k) {
+                 long lastBucket = ((long) nums[i - k] - Integer.MIN_VALUE) / ((long) t + 1);
+                 map.remove(lastBucket);
+             }
+             map.put(bucket, remappedNum);
+         }
+         return false;
+     }
+ }
+