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content/tracks/algorithms-101/leetcode/easy/2485/index.en.md

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+---
+title: 2485. Find the Pivot Integer
+seoTitle: LeetCode 2485. Find the Pivot Integer | Python solution and explanation
+description: 2485. Find the Pivot Integer
+toc: true
+tags: []
+categories: [Algorithms, LeetCode]
+date: 2024-01-01
+lastMod: 2024-01-01
+featuredImage: https://picsum.photos/700/155?grayscale
+weight: 2485
+---
+
+[LeetCode problem 2485](https://leetcode.com/problems/find-the-pivot-integer)
+
+```python
+class Solution:
+    def pivotInteger(self, n: int) -> int:
+        if n <= 1:
+            return n
+
+        ar = [1] * n
+
+        for i in range(1, n):
+            ar[i] = ar[i - 1] + i + 1
+
+        pivot = 1
+        while pivot < n:
+            left = ar[pivot]
+            right = ar[n - 1] - ar[pivot - 1]
+            if left == right:
+                return pivot + 1
+            pivot += 1
+
+        return -1
+```
+
+```python
+class Solution:
+    def pivotInteger(self, n: int) -> int:
+        y = n * (n + 1) // 2
+        x = int(sqrt(y))
+        return x if x * x == y else -1
+```
+
+```python
+class Solution:
+    def pivotInteger(self, n: int) -> int:
+        for x in range(1, n + 1):
+            if (1 + x) * x == (x + n) * (n - x + 1):
+                return x
+        return -1
+```

content/tracks/algorithms-101/leetcode/easy/2485/index.ru.md

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+---
+title: 2485. Find the Pivot Integer
+seoTitle: LeetCode 2485. Find the Pivot Integer | Python solution and explanation
+description: 2485. Find the Pivot Integer
+toc: true
+tags: []
+categories: [Algorithms, LeetCode]
+date: 2024-01-01
+lastMod: 2024-01-01
+featuredImage: https://picsum.photos/700/155?grayscale
+weight: 2485
+---
+
+[LeetCode problem 2485](https://leetcode.com/problems/find-the-pivot-integer)
+
+```python
+class Solution:
+    def pivotInteger(self, n: int) -> int:
+        if n <= 1:
+            return n
+
+        ar = [1] * n
+
+        for i in range(1, n):
+            ar[i] = ar[i - 1] + i + 1
+
+        pivot = 1
+        while pivot < n:
+            left = ar[pivot]
+            right = ar[n - 1] - ar[pivot - 1]
+            if left == right:
+                return pivot + 1
+            pivot += 1
+
+        return -1
+```
+
+```python
+class Solution:
+    def pivotInteger(self, n: int) -> int:
+        y = n * (n + 1) // 2
+        x = int(sqrt(y))
+        return x if x * x == y else -1
+```
+
+```python
+class Solution:
+    def pivotInteger(self, n: int) -> int:
+        for x in range(1, n + 1):
+            if (1 + x) * x == (x + n) * (n - x + 1):
+                return x
+        return -1
+```