fd

Author: liwentian

README.md

@@ -198,7 +198,7 @@
 |255|[Verify Preorder Sequence in Binary Search Tree](https://leetcode.com/problems/verify-preorder-sequence-in-binary-search-tree/)| [Java](https://github.com/dingjikerbo/leetcode/blob/master/solution/src/main/java/com/inuker/solution/VerifyPreorderSequenceInBinarySearchTree.java)|85|很简单，粗心错了|
 |256|[Paint House](https://leetcode.com/problems/paint-house/)| [Java](https://github.com/dingjikerbo/leetcode/blob/master/solution/src/main/java/com/inuker/solution/PaintHouse.java)|95|
 |257|[Binary Tree Paths](https://leetcode.com/problems/binary-tree-paths/)| [Java](https://github.com/dingjikerbo/leetcode/blob/master/solution/src/main/java/com/inuker/solution/BinaryTreePaths.java)|80|
-|259|[3Sum Smaller](https://leetcode.com/problems/3sum-smaller/)| [Java](https://github.com/dingjikerbo/leetcode/blob/master/solution/src/main/java/com/inuker/solution/ThreeSumSmaller.java)|95|
+|259|[3Sum Smaller](https://leetcode.com/problems/3sum-smaller/)| [Java](https://github.com/dingjikerbo/leetcode/blob/master/solution/src/main/java/com/inuker/solution/ThreeSumSmaller.java)|95|这题虽然简单，但是因为思维定式还是错了几次|
 |263|[Ugly Number](https://leetcode.com/problems/ugly-number/)| [Java](https://github.com/dingjikerbo/leetcode/blob/master/solution/src/main/java/com/inuker/solution/UglyNumber.java)|85|
 |264|[Ugly Number II](https://leetcode.com/problems/ugly-number-ii/)| [Java](https://github.com/dingjikerbo/leetcode/blob/master/solution/src/main/java/com/inuker/solution/UglyNumberII.java)|70|
 |265|[Paint House II](https://leetcode.com/problems/paint-house-ii)| [Java](https://github.com/dingjikerbo/leetcode/blob/master/solution/src/main/java/com/inuker/solution/PaintHouseII.java)|60|

google/src/main/java/com/leetcode/google/ThreeSumSmaller.java

@@ -0,0 +1,28 @@
+package com.leetcode.google;
+
+import java.util.Arrays;
+
+/**
+ * Created by liwentian on 2017/8/30.
+ */
+
+public class ThreeSumSmaller {
+    // -4 -1 -1 0 1 2 ,target=-5
+    public int threeSumSmaller(int[] nums, int target) {
+        Arrays.sort(nums);
+
+        int count = 0;
+        for (int i = 0; i < nums.length - 2; i++) {
+            for (int j = i + 1, k = nums.length - 1; j < k; ) {
+                if (nums[i] + nums[j] + nums[k] < target) {
+                    count += k - j;
+                    j++;
+                } else {
+                    k--;
+                }
+            }
+        }
+
+        return count;
+    }
+}

solution/src/main/java/com/inuker/solution/ThreeSumSmaller.java

@@ -11,10 +11,14 @@
  */
 public class ThreeSumSmaller {
 
+    /**
+     * 注意这里别画蛇添足的加上
+     * if (nums[i] > target) {
+     *     break;
+     * }
+     * 虽然后面的数大于等于nums[i]，但是有可能是负数，三个数之和还是可能小于target的
+     */
     public int threeSumSmaller(int[] nums, int target) {
-        if (nums.length < 3) {
-            return 0;
-        }
         Arrays.sort(nums);
 
         int count = 0;