update: 164 & 287

Author: hijiangtao

README.md

@@ -58,6 +58,7 @@ This is the solutions collection of my LeetCode submissions, most of them are pr
 |137|[Single Number II](https://leetcode.com/problems/single-number-ii/) | [JavaScript](./src/single-number-ii/res.js)|Medium|
 |151|[Reverse Words in a String](https://leetcode.com/problems/reverse-words-in-a-string/) | [JavaScript](./src/reverse-words-in-a-string/res.js)|Medium|
 |152|[Maximum Product Subarray](https://leetcode.com/problems/maximum-product-subarray/) | [JavaScript](./src/maximum-product-subarray/res.js)|Medium|
+|164|[Maximum Gap](https://leetcode.com/problems/maximum-gap/) | [JavaScript](./src/maximum-gap/res.js)|Hard|
 |165|[Compare Version Numbers](https://leetcode.com/problems/compare-version-numbers/) | [JavaScript](./src/compare-version-numbers/res.js)|Medium|
 |175|[Combine Two Tables](https://leetcode.com/problems/combine-two-tables/)| [SQL](./src/combine-two-tables/res.txt)|Easy|
 |176|[Second Highest Salary](https://leetcode.com/problems/second-highest-salary/)| [SQL](./src/second-highest-salary/res.txt)|Easy|
@@ -80,6 +81,7 @@ This is the solutions collection of my LeetCode submissions, most of them are pr
 |240|[Search a 2D Matrix II](https://leetcode.com/problems/search-a-2d-matrix-ii/) | [JavaScript](./src/search-a-2d-matrix-ii/res.js)|Medium|
 |274|[H-Index](https://leetcode.com/problems/h-index/) | [JavaScript](./src/h-index/res.js)|Medium|
 |275|[H-Index II](https://leetcode.com/problems/h-index-ii/) | [JavaScript](./src/h-index-ii/res.js)|Medium|
+|287|[Find the Duplicate Number](https://leetcode.com/problems/find-the-duplicate-number/) | [JavaScript](./src/find-the-duplicate-number/res.js)|Medium|
 |299|[Bulls and Cows](https://leetcode.com/problems/bulls-and-cows/) | [JavaScript](./src/bulls-and-cows/res.js)|Medium|
 |307|[Range Sum Query - Mutable](https://leetcode.com/problems/range-sum-query-mutable/) | [JavaScript](./src/range-sum-query-mutable/res.js)|Medium|
 |309|[Best Time to Buy and Sell Stock with Cooldown](https://leetcode.com/problems/best-time-to-buy-and-sell-stock-with-cooldown/) | [JavaScript](./src/best-time-to-buy-and-sell-stock-with-cooldown/res.js)|Medium|

src/find-the-duplicate-number/res.js

@@ -0,0 +1,22 @@
+/**
+ * Floyd判圈算法
+ * @param {number[]} nums
+ * @return {number}
+ */
+var findDuplicate = function(nums) {
+    let tortoise = nums[0];
+    let hare = nums[0];
+
+    do {
+      tortoise = nums[tortoise];
+      hare = nums[nums[hare]];
+    } while (tortoise !== hare);
+
+    hare = nums[0]
+    while (tortoise !== hare) {
+      hare = nums[hare]
+      tortoise = nums[tortoise]
+    }
+
+    return tortoise;
+};

src/maximum-gap/res.js

@@ -0,0 +1,48 @@
+/**
+ * https://leetcode-cn.com/problems/maximum-gap/solution/zui-da-jian-ju-by-leetcode/
+ * @param {number[]} nums
+ * @return {number}
+ */
+var maximumGap = function(nums) {
+    const len = nums.length;
+    if (len < 2) return 0;
+
+    let mini = Number.MAX_SAFE_INTEGER,
+        maxi = Number.MIN_SAFE_INTEGER;
+
+    nums.forEach(e => {
+        if (e < mini) {
+            mini = e;
+        }
+        if (e > maxi) {
+            maxi = e;
+        }
+    })
+
+
+    let bucketSize = Math.max(1, (maxi - mini) / (nums.length - 1));        // bucket size or capacity
+    let bucketNum = parseInt((maxi - mini) / bucketSize) + 1;                        // number of buckets
+    const buckets = [];
+    for (let index = 0; index < bucketNum; index++) {
+        buckets.push({});
+    }
+
+    // console.log(buckets);
+    nums.forEach(num => {
+        let bucketIdx = parseInt((num - mini) / bucketSize);                          // locating correct bucket
+        // console.log('bucketIdx is ', bucketIdx);
+        buckets[bucketIdx].used = true;
+        buckets[bucketIdx].minval = Math.min(num, buckets[bucketIdx].minval || Number.MAX_SAFE_INTEGER);
+        buckets[bucketIdx].maxval = Math.max(num, buckets[bucketIdx].maxval || Number.MIN_SAFE_INTEGER);
+    });
+
+    let prevBucketMax = mini, maxGap = 0;
+    buckets.forEach(bucket => {
+        if (bucket.used) {
+            maxGap = Math.max(maxGap, bucket.minval - prevBucketMax);
+            prevBucketMax = bucket.maxval;
+        }
+    });
+
+    return maxGap;
+};