Add Arrays/15_3Sum.java

Author: seanprashad

Arrays/15_3Sum.java

@@ -0,0 +1,32 @@
+class Solution {
+    public List<List<Integer>> threeSum(int[] nums) {
+        List<List<Integer>> result = new ArrayList<>();
+        
+        Arrays.sort(nums);
+
+        for (int i = 0; i < 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 == 0) {
+                    result.add(Arrays.asList(nums[i], nums[j], nums[k]));
+                    ++j;
+                    
+                    while (j < k && nums[j] == nums[j-1]) { 
+                        ++j; 
+                    }
+                } else if (sum > 0) {
+                    --k;
+                } else {
+                    ++j;
+                }
+            }
+        }
+
+        return result;
+    }
+}