update readme

Author: yennanliu

README.md

@@ -287,7 +287,7 @@
 840 | [Magic Squares In Grid](https://leetcode.com/problems/magic-squares-in-grid/) | [Python](./leetcode_python/Array/magic-squares-in-grid.py) | _O(m * n)_ | _O(1)_ | Easy |`complex`| AGAIN (not start)
 842 | [Split Array into Fibonacci Sequence](https://leetcode.com/problems/split-array-into-fibonacci-sequence/) | [Python](./leetcode_python/Array/split-array-into-fibonacci-sequence.py) | _O(n^3)_ | _O(n)_ | Medium |check `# 306 Addictive Number`, `basic`, `dfs`, `fibonacci`| AGAIN* (not start)
 845 | [Longest Mountain in Array](https://leetcode.com/problems/longest-mountain-in-array/) | [Python](./leetcode_python/Array/longest-mountain-in-array.py) | _O(n)_ | _O(1)_ | Medium |`basic`, `trick`| AGAIN* (not start) 
-849 | [Maximize Distance to Closest Person](https://leetcode.com/problems/maximize-distance-to-closest-person/) | [Python](./leetcode_python/Array/maximize-distance-to-closest-person.py), [Java](./leetcode_java/src/main/java/LeetCodeJava/Array/MaximizeDistanceToClosestPerson.java) | _O(n)_ | _O(1)_ | Medium |`basic`, google, 2 pointers| AGAIN (1)
+849 | [Maximize Distance to Closest Person](https://leetcode.com/problems/maximize-distance-to-closest-person/) | [Python](./leetcode_python/Array/maximize-distance-to-closest-person.py), [Java](./leetcode_java/src/main/java/LeetCodeJava/Array/MaximizeDistanceToClosestPerson.java) | _O(n)_ | _O(1)_ | Medium |`basic`, 2 pointers, LC 855, google| AGAIN***** (1)
 860 | [Lemonade Change](https://leetcode.com/problems/lemonade-change/) | [Python](./leetcode_python/Array/lemonade-change.py) | _O(n)_ | _O(1)_ | Easy |amazon| OK* (2)
 0868 | [Transpose Matrix](https://leetcode.com/problems/transpose-matrix/) | [Python](./leetcode_python/Array/transpose-matrix.py) | _O(r * c)_ | _O(1)_ | Easy |`basic`| OK*
 885 | [Spiral Matrix III](https://leetcode.com/problems/spiral-matrix-iii/) | [Python](./leetcode_python/Array/spiral-matrix-iii.py) | _O(max(m, n)^2)_ | _O(1)_ | Medium  |`basic`| AGAIN* (not start)
@@ -528,7 +528,7 @@
 373 | [Find K Pairs with Smallest Sums](https://leetcode.com/problems/find-k-pairs-with-smallest-sums/) | [Python](./leetcode_python/Heap/find-k-pairs-with-smallest-sums.py)  | _O(k * log(min(n, m, k)))_ | _O(min(n, m, k))_ | Medium || AGAIN (not start)
 378 | [Kth Smallest Element in a Sorted Matrix](https://leetcode.com/problems/kth-smallest-element-in-a-sorted-matrix/) | [Python](./leetcode_python/Heap/kth-smallest-element-in-a-sorted-matrix.py)  | _O(k * log(min(n, m, k)))_ | _O(min(n, m, k))_ | Medium | LintCode | AGAIN (not start)
 846 | [Hand of Straights](https://leetcode.com/problems/hand-of-straights/) | [Python](./leetcode_python/Heap/hand-of-straights.py), [Java](./leetcode_java/src/main/java/LeetCodeJava/Heap/HandOfStraights.java)| _O(nlogn)_ | _O(n)_ | Medium |LC 1296, good basic, Treemap, hashmap, google| OK*** (2)
-855 | [Exam Room](https://leetcode.com/problems/exam-room/) | [Python](./leetcode_python/Heap/exam-room.py), [Java](./leetcode_java/src/main/java/LeetCodeJava/Heap/ExamRoom.java)  | seat: _O(logn)_ <br> leave: _O(logn)_ | _O(n)_ | Medium | treeSet, BST, Hash, `trick`, google | AGAIN* (3) (not start)
+855 | [Exam Room](https://leetcode.com/problems/exam-room/) | [Python](./leetcode_python/Heap/exam-room.py), [Java](./leetcode_java/src/main/java/LeetCodeJava/Heap/ExamRoom.java)  | seat: _O(logn)_ <br> leave: _O(logn)_ | _O(n)_ | Medium | treeSet, BST, Hash, `trick`, LC 849, google | AGAIN* (3) (not start)
 295 | [Find Median from Data Stream](https://leetcode.com/problems/find-median-from-data-stream/) | [Python](./leetcode_python/Heap/find_median_from_data_stream.py), [Java](./leetcode_java/src/main/java/LeetCodeJava/Heap/FindMedianFromDataStream.java)  | | | Hard |Curated Top 75, priority queue, trick ,heap, stream, `amazon`|  AGAIN****** (6)
 703 | [Kth Largest Element in a Stream](https://leetcode.com/problems/kth-largest-element-in-a-stream/) | [Python](./leetcode_python/Heap/kth_largest_element_in_a_stream.py), [Java](./leetcode_java/src/main/java/LeetCodeJava/Heap/KthLargestElementInAStream.java)  | | | Easy |heap, priority queue, `amazon`|  AGAIN***** (4)
 1046| [Last Stone Weight](https://leetcode.com/problems/last-stone-weight/) |  [Python](./leetcode_python/Heap/last-stone-weight.py), [Java](./leetcode_java/src/main/java/LeetCodeJava/Heap/LastStoneWeight.java)||| Easy |Heap, Priority Queue| OK