solves #2485: Find the Pivot Integer in java

Author: anishLearnsToCode

README.md

@@ -783,7 +783,7 @@
 | 2469 | [Convert the Temperature](https://leetcode.com/problems/convert-the-temperature)                                                                                       |                                                                                    [![Java](assets/java.png)](src/ConvertTheTemperature.java)                                                                                    |                                                                                                                                   |
 | 2475 | [Number of Unequal Triplets in Array](https://leetcode.com/problems/number-of-unequal-triplets-in-array)                                                               |                                                                               [![Java](assets/java.png)](src/NumberOfUnequalTripletsInArray.java)                                                                                |                                                                                                                                   |
 | 2481 | [Minimum Cuts to Divide a Circle](https://leetcode.com/problems/minimum-cuts-to-divide-a-circle)                                                                       |                                                                                 [![Java](assets/java.png)](src/MinimumCutsToDivideACircle.java)                                                                                  |                                                                                                                                   |
-| 2485 | [Find the Pivot Integer](https://leetcode.com/problems/find-the-pivot-integer)                                                                                         |                                                                                                                                                                                                                                  |                                                                                                                                   |
+| 2485 | [Find the Pivot Integer](https://leetcode.com/problems/find-the-pivot-integer)                                                                                         |                                                                                     [![Java](assets/java.png)](src/FindThePivotInteger.java)                                                                                     |                                                                                                                                   |
 | 2490 | [Circular Sentence](https://leetcode.com/problems/circular-sentence)                                                                                                   |                                                                                                                                                                                                                                  |                                                                                                                                   |
 | 2492 | [Minimum Score of a Path Between Two Cities](https://leetcode.com/problems/minimum-score-of-a-path-between-two-cities)                                                 |                                                                       [![Python](assets/python.png)](python/minimum_score_of_a_path_between_two_cities.py)                                                                       |                                                                                                                                   |
 | 2496 | [Maximum Value of a String in an Array](https://leetcode.com/problems/maximum-value-of-a-string-in-an-array)                                                           |                                                                                                                                                                                                                                  |                                                                                                                                   |

src/FindThePivotInteger.java

@@ -0,0 +1,19 @@
+// https://leetcode.com/problems/find-the-pivot-integer
+// T: O(N)
+// S: O(1)
+
+public class FindThePivotInteger {
+    public int pivotInteger(int n) {
+        for (int pivot = 1, left = 1, right = summation(n) ; pivot <= n ; pivot++) {
+            if (left == right) return pivot;
+            if (left > right) break;
+            left += pivot + 1;
+            right -= pivot;
+        }
+        return -1;
+    }
+
+    private int summation(int n) {
+        return (n * (n + 1)) / 2;
+    }
+}