update 0016 Solution for Java

Author: EndaLin

solution/0000-0099/0016.3Sum Closest/Solution.java

@@ -1,17 +1,43 @@
 class Solution {
     public int threeSumClosest(int[] nums, int target) {
-        int result = nums[0]+nums[1]+nums[2];
         Arrays.sort(nums);
-        for(int i = 0;i<nums.length-2;i++){
-            int start = i+1,end=nums.length-1;
-            while(start<end){
-                int cache = nums[i]+nums[start]+nums[end];
-                if(Math.abs(cache-target)<Math.abs(result-target)) result = cache;
-                if(cache < target ) start++;
-                else if(cache > target) end--;
-                else return result;
+        int bestAns = 100000;
+        for (int i = 0;i + 2 < nums.length;i++) {
+            if (i != 0 && nums[i] == nums[i - 1]) {
+                continue;
+            }
+            int j = i + 1, k = nums.length - 1;
+            while (j < k) {
+                int sum = nums[i] + nums[j] + nums[k];
+                if (sum == target) {
+                    return sum;
+                }
+                if (Math.abs(target - bestAns) > Math.abs(target - sum)) {
+                    bestAns = sum;
+                }
+                if (sum > target) {
+                    int k0 = k - 1;
+                    while (j < k0 && nums[k] == nums[k0]) {
+                        k0--;
+                    }
+                    if (j == k0) {
+                        break;
+                    } else {
+                        k = k0;
+                    }
+                } else {
+                    int j0 = j + 1;
+                    while (j0 < j && nums[j] == nums[j0]) {
+                        j0++;
+                    }
+                    if (j0 == k) {
+                        break;
+                    } else {
+                        j = j0;
+                    }
+                }
             }
         }
-        return result;
+        return bestAns;
     }
-}
+}