allcoding1_official

if not intervals:
        return 0
    
    intervals.sort(key=lambda x: x[0])  # Sort intervals based on start points
    merged_intervals = [intervals[0]]  # Initialize merged intervals with the first interval
    
    for interval in intervals[1:]:
        prev_interval = merged_intervals[-1]
        
        if interval[0] <= prev_interval[1]:  # If overlapping with previous interval
            prev_interval[1] = max(prev_interval[1], interval[1])  # Merge intervals
        else:
            merged_intervals.append(interval)  # Add non-overlapping interval
    
    total_length = sum(end - start for start, end in merged_intervals)
    return total_length

# Example usage:
intervals = [(1, 3), (2, 6), (8, 10), (15, 18)]
total_length_covered = merge_intervals(intervals)
print("Total length covered after merging overlapping intervals:", total_length_covered)