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def binary_search(arr, target):
    left, right = 0, len(arr) - 1
    while left <= right:
        mid = (left + right) // 2
        if arr[mid] == target:
            return mid
        elif arr[mid] < target:
            left = mid + 1
        else:
            right = mid - 1
    return -1

AI Explanation:

This function implements binary search algorithm.

Line 1: Function takes sorted array and target value
Line 2: Initialize two pointers (left=start, right=end)
Line 3-9: While loop narrows search range
Line 4: Calculate middle index using floor division
Line 5-6: If middle element equals target, return index
Line 7-8: If target is larger, search right half
Line 9-10: If target is smaller, search left half
Line 11: Return -1 if target not found

Time Complexity: O(log n)
Space Complexity: O(1)

const UserCard = ({ user }) => {
  const [isExpanded, setExpanded] = useState(false);
  
  useEffect(() => {
    console.log("User rendered:", user.name);
  }, [user]);
  
  return (
    <div onClick={() => setExpanded(!isExpanded)}>
      <h3>{user.name}</h3>
      {isExpanded && <p>{user.bio}</p>}
    </div>
  );
};

AI Explanation:

React functional component displaying user information.

Line 1: Component receives user prop via destructuring
Line 2: useState hook manages expansion state (initially false)
Line 4-6: useEffect logs user name on mount/update
Line 5: Console log runs when user object changes
Line 6: Dependency array [user] triggers effect on user change
Line 8-12: JSX returns clickable card
Line 9: onClick toggles isExpanded state
Line 10: Displays user name in h3
Line 11: Conditional rendering shows bio when expanded

React Hooks: useState for state, useEffect for side effects
Pattern: Collapsible card with toggle functionality