Optimized gas costs in ceilDiv (#4553)

contracts/utils/math/Math.sol

@@ -110,8 +110,14 @@ library Math {
             return a / b;
         }
 
-        // (a + b - 1) / b can overflow on addition, so we distribute.
-        return a == 0 ? 0 : (a - 1) / b + 1;
+        // The following calculation ensures accurate ceiling division without overflow.
+        // Since a is non-zero, (a - 1) / b will not overflow.
+        // The largest possible result occurs when (a - 1) / b is type(uint256).max,
+        // but the largest value we can obtain is type(uint256).max - 1, which happens
+        // when a = type(uint256).max and b = 1.
+        unchecked {
+            return a == 0 ? 0 : (a - 1) / b + 1;
+        }
     }
 
     /**