Add solution #16

Author: JoshCrozier

README.md

@@ -21,6 +21,7 @@
 13|[Roman to Integer](./0013-roman-to-integer.js)|Easy|
 14|[Longest Common Prefix](./0014-longest-common-prefix.js)|Easy|
 15|[3Sum](./0015-3sum.js)|Medium|
+16|[3Sum Closest](./0016-3sum-closest.js)|Medium|
 17|[Letter Combinations of a Phone Number](./0017-letter-combinations-of-a-phone-number.js)|Medium|
 19|[Remove Nth Node From End of List](./0019-remove-nth-node-from-end-of-list.js)|Medium|
 20|[Valid Parentheses](./0020-valid-parentheses.js)|Easy|

solutions/0016-3sum-closest.js

@@ -0,0 +1,40 @@
+/**
+ * 16. 3Sum Closest
+ * https://leetcode.com/problems/3sum-closest/
+ * Difficulty: Medium
+ *
+ * Given an integer array nums of length n and an integer target, find three integers
+ * in nums such that the sum is closest to target.
+ *
+ * Return the sum of the three integers.
+ *
+ * You may assume that each input would have exactly one solution.
+ */
+
+/**
+ * @param {number[]} nums
+ * @param {number} target
+ * @return {number}
+ */
+var threeSumClosest = function(nums, target) {
+  const sums = new Set();
+
+  nums.sort((a, b) => a - b);
+
+  for (let i = 0; i < nums.length - 2; i++) {
+    let j = i + 1;
+    let k = nums.length - 1;
+
+    while (j < k) {
+      const sum = nums[i] + nums[j] + nums[k];
+      sums.add(sum);
+      if (sum > target) {
+        k--;
+      } else {
+        j++;
+      }
+    }
+  }
+
+  return [...sums].reduce((p, c) => Math.abs(c - target) < Math.abs(p - target) ? c : p);
+};