Create 2485.py

Author: chandansgowda

2001-2500/2485.py

@@ -0,0 +1,13 @@
+class Solution:
+    def pivotInteger(self, n: int) -> int:
+        tsum = n*(n+1) // 2
+        l,r = 1,n+1
+        while l<r:
+            m = (l+r)//2
+            lsum = m*(m+1)//2
+            rsum = tsum-lsum-m
+            if lsum<rsum:
+                l=m+1
+            else:
+                r=m
+        return l if l*(l-1)//2==tsum-(l+1)*l//2 else -1