12.20

Author: zzxboy1

README.md

@@ -17,6 +17,7 @@
 |13|[Roman to Integer](https://leetcode.com/problems/roman-to-integer/)| [JavaScript](./algorithms/Roman to Integer.js)|Easy|
 |14|[Longest Common Prefix](https://leetcode.com/problems/longest-common-prefix/)| [JavaScript](./algorithms/Longest Common Prefix.js)|Easy|
 |15|[3Sum](https://leetcode.com/problems/3sum/)| [JavaScript](./algorithms/3Sum.js)|Medium|
+|16|[3Sum Closest](https://leetcode.com/problems/3sum-closest/)| [JavaScript](./algorithms/3Sum Closest.js)|Medium|
 |371|[Sum of Two Integers](https://leetcode.com/problems/sum-of-two-integers/)| [JavaScript](./algorithms/Sum of Two Integers.js)|Easy|
 |372|[Super Pow](https://leetcode.com/problems/super-pow/)| [JavaScript](./algorithms/SuperPow.js)|Medium|
 

algorithms/3Sum Closest.js

@@ -0,0 +1,33 @@
+/**
+ * @param {number[]} nums
+ * @param {number} target
+ * @return {number}
+ */
+var threeSumClosest = function(nums, target) {
+     nums.sort(function(a,b){
+        return a-b;
+    })
+    var result=null,len=nums.length;
+    for(var i=0;i<len;i++){
+        if (nums[i]===nums[i-1]){
+            continue;
+        }
+        var low=i+1,high=len-1;
+        while(low<high){
+            var sum=nums[low]+nums[high]+nums[i];
+            if(sum===target){
+                return target;
+            }
+            else if(sum<target){
+                low++;
+            }
+            else{
+                high--;
+            }
+            if(result ===null || Math.abs(sum-target)<Math.abs(result-target)){
+                result=sum;
+            }
+        }
+    }
+    return result;
+};

algorithms/TwoSum.js

@@ -4,14 +4,13 @@
  * @return {number[]}
  */
 var twoSum = function(nums, target) {
-    var newArray=[];
-    var l=nums.length
-    for(var i=0;i<l;i++){
-        for(var j=i+1;j<l;j++){
-            if(nums[i]+nums[j]===target){
-                newArray.push(i,j);
-                return newArray;
-            }
-        } 
+    var temp = [];
+    for (var i = 0; i < nums.length; i++) {
+        if (temp[target - nums[i]] !== undefined) {
+            return [temp[target - nums[i]], i];
+        }
+        if (!temp[nums[i]]) {
+            temp[nums[i]] = i;
+        }
     }
-};
+};