solves 3 sum closest

Author: anishLearnsToCode

README.md

@@ -24,6 +24,7 @@
 |  13  | [Roman To Integer](https://leetcode.com/problems/roman-to-integer/)                                                                                       |                                    [![Java](assets/java.png)](src/RomanToInteger.java) [![Python](assets/python.png)](python/roman_to_integer.py)                                    | [![java-yt](assets/java-yt.png)](https://youtu.be/BCue_mO_81A) [![python-yt](assets/python-yt.png)](https://youtu.be/8h_yGTNvKMA) |
 |  14  | [Longest Common Prefix](https://leetcode.com/problems/longest-common-prefix/)                                                                             |                               [![Java](assets/java.png)](src/LongestCommonPrefix.java) [![Python](assets/python.png)](python/longest_common_prefix.py)                               |                                                                                                                                   |
 |  15  | [3Sum](https://leetcode.com/problems/3sum)                                                                                                                |                                                                    [![Java](assets/java.png)](src/ThreeSum.java)                                                                     |                                                                                                                                   |
+|  16  | [3Sum Closest](https://leetcode.com/problems/3sum-closest)                                                                                                |                                                                 [![Java](assets/java.png)](src/ThreeSumClosest.java)                                                                 |                                                                                                                                   |
 |  20  | [ValidParentheses](https://leetcode.com/problems/valid-parentheses/)                                                                                      |                                  [![Java](assets/java.png)](src/ValidParentheses.java) [![Python](assets/python.png)](python/valid_parentheses.py)                                   |                                                                                                                                   |
 |  21  | [Merge 2 Sorted Lists](https://leetcode.com/problems/merge-two-sorted-lists/)                                                                             |                                [![Java](assets/java.png)](src/Merge2SortedLists.java) [![Python](assets/python.png)](python/merge_2_sorted_lists.py)                                 |                                                                                                                                   |
 |  26  | [Remove Duplicates From Sorted Array](https://leetcode.com/problems/remove-duplicates-from-sorted-array/)                                                 |                  [![Java](assets/java.png)](src/RemoveDuplicatesFromSortedArray.java) [![Python](assets/python.png)](python/remove_duplicates_from_sorted_array.py)                  |                                                                                                                                   |

src/ThreeSumClosest.java

@@ -0,0 +1,28 @@
+// https://leetcode.com/problems/3sum-closest
+// T: O(n^2)
+// S: O(1)
+
+import java.util.Arrays;
+
+public class ThreeSumClosest {
+    public static void main(String[] args) {
+        System.out.println(threeSumClosest(new int[] {0, 2, 1, -3}, 1));
+    }
+
+    public static int threeSumClosest(int[] nums, int target) {
+        Arrays.sort(nums);
+        int closestSum = nums[0] + nums[1] + nums[2];
+        for (int i = 0 ; i < nums.length - 2 ; i++) {
+            for (int j = i + 1, k = nums.length - 1 ; j < k ; ) {
+                int sum = nums[i] + nums[j] + nums[k];
+                if (sum == target) return sum;
+                if (Math.abs(sum - target) < Math.abs(closestSum - target)) {
+                    closestSum = sum;
+                }
+                else if (sum > target) k--;
+                else j++;
+            }
+        }
+        return closestSum;
+    }
+}