class Solution:
    def isPalindrome(self, s: str) -> bool:
        s = s.lower()
        new_s = ''
        for char in s:
            if char.isalnum(): 
                new_s += char
        if new_s == new_s[::-1]:
            return True
        else:
            return False

// Zero-copy network IO implementation
async fn zero_copy_transfer(
    input: &mut TcpStream,
    output: &mut TcpStream,
    size: usize
) -> Result<usize> {
    // Use sendfile system call for zero-copy
    let bytes_transferred = sendfile(output.as_raw_fd(), input.as_raw_fd(), None, size)?;
    Ok(bytes_transferred)
}

// File transfer using mmap
fn mmap_file_transfer(file_path: &str, stream: &mut TcpStream) -> Result<()> {
    let file = File::open(file_path)?;
    let mmap = unsafe { Mmap::map(&file)? };

    // Directly send memory-mapped data
    stream.write_all(&mmap)?;
    stream.flush()?;

    Ok(())
}

// TCP parameter optimization configuration
fn optimize_tcp_socket(socket: &TcpSocket) -> Result<()> {
    // Disable Nagle's algorithm to reduce small packet latency
    socket.set_nodelay(true)?;

    // Increase TCP buffer size
    socket.set_send_buffer_size(64 * 1024)?;
    socket.set_recv_buffer_size(64 * 1024)?;

    // Enable TCP Fast Open
    socket.set_tcp_fastopen(true)?;

    // Adjust TCP keepalive parameters
    socket.set_keepalive(true)?;

    Ok(())
}

// Asynchronous IO batch processing
async fn batch_async_io(requests: Vec<Request>) -> Result<Vec<Response>> {
    let futures = requests.into_iter().map(|req| {
        async move {
            // Process multiple requests in parallel
            process_request(req).await
        }
    });

    // Use join_all for parallel execution
    let results = join_all(futures).await;

    // Collect results
    let mut responses = Vec::new();
    for result in results {
        responses.push(result?);
    }

    Ok(responses)
}

const http = require('http');
const fs = require('fs');

const server = http.createServer((req, res) => {
    // File reading and sending involve multiple copies
    fs.readFile('large_file.txt', (err, data) => {
        if (err) {
            res.writeHead(500);
            res.end('Error');
        } else {
            res.writeHead(200, {'Content-Type': 'text/plain'});
            res.end(data); // Data copying occurs here
        }
    });
});

server.listen(60000);

package main

import (
    "fmt"
    "net/http"
    "os"
)

func handler(w http.ResponseWriter, r *http.Request) {
    // Use io.Copy for file transfer
    file, err := os.Open("large_file.txt")
    if err != nil {
        http.Error(w, "File not found", 404)
        return
    }
    defer file.Close()

    // io.Copy still involves data copying
    _, err = io.Copy(w, file)
    if err != nil {
        fmt.Println("Copy error:", err)
    }
}

func main() {
    http.HandleFunc("/", handler)
    http.ListenAndServe(":60000", nil)
}

use std::io::prelude::*;
use std::net::TcpListener;
use std::fs::File;
use memmap2::Mmap;

async fn handle_client(mut stream: TcpStream) -> Result<()> {
    // Use mmap for zero-copy file transfer
    let file = File::open("large_file.txt")?;
    let mmap = unsafe { Mmap::map(&file)? };

    // Directly send memory-mapped data
    stream.write_all(&mmap)?;
    stream.flush()?;

    Ok(())
}

fn main() -> Result<()> {
    let listener = TcpListener::bind("127.0.0.1:60000")?;

    for stream in listener.incoming() {
        let stream = stream?;
        tokio::spawn(async move {
            if let Err(e) = handle_client(stream).await {
                eprintln!("Error handling client: {}", e);
            }
        });
    }

    Ok(())
}

// Video chunked transfer
async fn stream_video_chunked(
    file_path: &str,
    stream: &mut TcpStream,
    chunk_size: usize
) -> Result<()> {
    let file = File::open(file_path)?;
    let mmap = unsafe { Mmap::map(&file)? };

    // Send video data in chunks
    for chunk in mmap.chunks(chunk_size) {
        stream.write_all(chunk).await?;
        stream.flush().await?;

        // Control transmission rate
        tokio::time::sleep(Duration::from_millis(10)).await;
    }

    Ok(())
}

// Video stream connection reuse
struct VideoStreamPool {
    connections: Vec<TcpStream>,
    max_connections: usize,
}

impl VideoStreamPool {
    async fn get_connection(&mut self) -> Option<TcpStream> {
        if self.connections.is_empty() {
            self.create_new_connection().await
        } else {
            self.connections.pop()
        }
    }

    fn return_connection(&mut self, conn: TcpStream) {
        if self.connections.len() < self.max_connections {
            self.connections.push(conn);
        }
    }
}

// UDP low-latency transfer
async fn udp_low_latency_transfer(
    socket: &UdpSocket,
    data: &[u8],
    addr: SocketAddr
) -> Result<()> {
    // Set UDP socket to non-blocking mode
    socket.set_nonblocking(true)?;

    // Send data
    socket.send_to(data, addr).await?;

    Ok(())
}

// Trade data batch processing
async fn batch_trade_processing(trades: Vec<Trade>) -> Result<()> {
    // Batch serialization
    let mut buffer = Vec::new();
    for trade in trades {
        trade.serialize(&mut buffer)?;
    }

    // Batch sending
    socket.send(&buffer).await?;

    Ok(())
}

// DPDK network IO example
fn dpdk_packet_processing() {
    // Initialize DPDK
    let port_id = 0;
    let queue_id = 0;

    // Directly operate on network card to send and receive packets
    let packet = rte_pktmbuf_alloc(pool);
    rte_eth_rx_burst(port_id, queue_id, &mut packets, 32);
}

// RDMA zero-copy transfer
fn rdma_zero_copy_transfer() {
    // Establish RDMA connection
    let context = ibv_open_device();
    let pd = ibv_alloc_pd(context);

    // Register memory region
    let mr = ibv_reg_mr(pd, buffer, size);

    // Zero-copy data transfer
    post_send(context, mr);
}

// Adaptive compression algorithm
fn adaptive_compression(data: &[u8]) -> Vec<u8> {
    // Choose compression algorithm based on data type
    if is_text_data(data) {
        compress_with_gzip(data)
    } else if is_binary_data(data) {
        compress_with_lz4(data)
    } else {
        data.to_vec() // No compression
    }
}

sudo ./sysmaint --dry-run

sudo ./sysmaint

# Weekly automated maintenance
sudo ./sysmaint --auto --quiet

sudo systemctl enable --now sysmaint.timer

git clone https://github.com/Harery/SYSMAINT.git
cd SYSMAINT
sudo ./sysmaint --dry-run

// Zero-latency interrupt handling
#[inline(always)]
unsafe fn handle_realtime_interrupt() {
    // Disable interrupt nesting
    disable_interrupts();

    // Quickly process critical tasks
    process_critical_task();

    // Enable interrupts
    enable_interrupts();
}

// Real-time task scheduling
struct RealtimeScheduler {
    // Priority queues
    priority_queues: [VecDeque<RealtimeTask>; 8],
    // Currently running task
    current_task: Option<RealtimeTask>,
    // Scheduling policy
    scheduling_policy: SchedulingPolicy,
}

impl RealtimeScheduler {
    fn schedule_task(&mut self, task: RealtimeTask) {
        // Insert into queue based on priority
        let priority = task.priority as usize;
        self.priority_queues[priority].push_back(task);

        // Check if current task needs to be preempted
        if let Some(current) = &self.current_task {
            if task.priority > current.priority {
                self.preempt_current_task();
            }
        }
    }

    fn preempt_current_task(&mut self) {
        // Save current task context
        if let Some(current) = self.current_task.take() {
            // Put current task back into queue
            let priority = current.priority as usize;
            self.priority_queues[priority].push_front(current);
        }

        // Schedule highest priority task
        self.schedule_highest_priority_task();
    }
}

// Cache-friendly data structure
#[repr(C)]
#[derive(Clone, Copy)]
struct RealtimeData {
    // Hot data together
    timestamp: u64,      // 8 bytes
    sequence: u32,       // 4 bytes
    status: u16,         // 2 bytes
    reserved: u16,       // 2 bytes padding
    // Cold data at the end
    metadata: [u8; 64],  // 64 bytes
}

// Memory pool pre-allocation
struct RealtimeMemoryPool {
    // Pre-allocated memory blocks
    memory_blocks: Vec<RealtimeData>,
    // Free list
    free_list: Vec<usize>,
    // Usage count
    usage_count: AtomicUsize,
}

impl RealtimeMemoryPool {
    fn new(capacity: usize) -> Self {
        let mut memory_blocks = Vec::with_capacity(capacity);
        let mut free_list = Vec::with_capacity(capacity);

        // Pre-allocate all memory blocks
        for i in 0..capacity {
            memory_blocks.push(RealtimeData::default());
            free_list.push(i);
        }

        Self {
            memory_blocks,
            free_list,
            usage_count: AtomicUsize::new(0),
        }
    }

    fn allocate(&mut self) -> Option<&mut RealtimeData> {
        if let Some(index) = self.free_list.pop() {
            self.usage_count.fetch_add(1, Ordering::Relaxed);
            Some(&mut self.memory_blocks[index])
        } else {
            None
        }
    }

    fn deallocate(&mut self, data: &mut RealtimeData) {
        // Calculate index
        let index = (data as *mut RealtimeData as usize - self.memory_blocks.as_ptr() as usize) / std::mem::size_of::<RealtimeData>();

        self.free_list.push(index);
        self.usage_count.fetch_sub(1, Ordering::Relaxed);
    }
}

// Fast interrupt handler
#[naked]
unsafe extern "C" fn fast_interrupt_handler() {
    asm!(
        // Save critical registers
        "push rax",
        "push rcx",
        "push rdx",
        "push rdi",
        "push rsi",

        // Call C handler function
        "call realtime_interrupt_handler",

        // Restore registers
        "pop rsi",
        "pop rdi",
        "pop rdx",
        "pop rcx",
        "pop rax",

        // Interrupt return
        "iretq",
        options(noreturn)
    );
}

// Real-time interrupt handler function
#[inline(always)]
unsafe fn realtime_interrupt_handler() {
    // Read interrupt status
    let status = read_interrupt_status();

    // Quickly handle different types of interrupts
    match status.interrupt_type {
        InterruptType::Timer => handle_timer_interrupt(),
        InterruptType::Network => handle_network_interrupt(),
        InterruptType::Disk => handle_disk_interrupt(),
        InterruptType::Custom => handle_custom_interrupt(),
    }

    // Clear interrupt flag
    clear_interrupt_flag(status);
}

const http = require('http');

// Real-time data processing
const server = http.createServer((req, res) => {
    // Problem: Event loop latency is unpredictable
    const start = process.hrtime.bigint();

    // Process real-time data
    const data = processRealtimeData(req.body);

    const end = process.hrtime.bigint();
    const latency = Number(end - start) / 1000; // microseconds

    // Problem: GC pauses affect real-time performance
    res.writeHead(200, {'Content-Type': 'application/json'});
    res.end(JSON.stringify({ 
        result: data,
        latency: latency 
    }));
});

server.listen(60000);

function processRealtimeData(data) {
    // Problem: JavaScript's dynamic type checking increases latency
    return data.map(item => {
        return {
            timestamp: Date.now(),
            value: item.value * 2
        };
    });
}

package main

import (
    "encoding/json"
    "net/http"
    "runtime"
    "time"
)

func init() {
    // Set GOMAXPROCS
    runtime.GOMAXPROCS(runtime.NumCPU())

    // Set GC parameters
    debug.SetGCPercent(10) // Reduce GC frequency
}

// Real-time data processing
func realtimeHandler(w http.ResponseWriter, r *http.Request) {
    startTime := time.Now()

    // Use sync.Pool to reduce memory allocation
    buffer := bufferPool.Get().([]byte)
    defer bufferPool.Put(buffer)

    // Process real-time data
    var data RealtimeData
    if err := json.NewDecoder(r.Body).Decode(&data); err != nil {
        http.Error(w, err.Error(), http.StatusBadRequest)
        return
    }

    // Real-time processing logic
    result := processRealtimeData(data)

    latency := time.Since(startTime).Microseconds()

    // Return result
    response := map[string]interface{}{
        "result": result,
        "latency": latency,
    }

    json.NewEncoder(w).Encode(response)
}

func main() {
    http.HandleFunc("/realtime", realtimeHandler)
    http.ListenAndServe(":60000", nil)
}

type RealtimeData struct {
    Timestamp int64   `json:"timestamp"`
    Value     float64 `json:"value"`
}

var bufferPool = sync.Pool{
    New: func() interface{} {
        return make([]byte, 1024)
    },
}

use std::time::{Instant, Duration};
use std::sync::atomic::{AtomicBool, Ordering};
use std::arch::x86_64::{__rdtsc, _mm_pause};

// Real-time data processing structure
#[repr(C)]
#[derive(Clone, Copy)]
struct RealtimeData {
    timestamp: u64,
    sequence: u32,
    data: [f64; 8],
    status: u8,
}

// Real-time processor
struct RealtimeProcessor {
    // Memory pool
    memory_pool: RealtimeMemoryPool,
    // Processing status
    processing: AtomicBool,
    // Performance metrics
    metrics: RealtimeMetrics,
}

impl RealtimeProcessor {
    // Zero-copy data processing
    #[inline(always)]
    unsafe fn process_data(&self, data: &RealtimeData) -> ProcessResult {
        // Use SIMD instructions for vectorized processing
        let result = self.simd_process(data);

        // Atomic operation to update status
        self.metrics.update_metrics();

        result
    }

    // SIMD vectorized processing
    #[target_feature(enable = "avx2")]
    unsafe fn simd_process(&self, data: &RealtimeData) -> ProcessResult {
        use std::arch::x86_64::*;

        // Load data into SIMD registers
        let data_ptr = data.data.as_ptr() as *const __m256d;
        let vec_data = _mm256_load_pd(data_ptr);

        // SIMD computation
        let result = _mm256_mul_pd(vec_data, _mm256_set1_pd(2.0));

        // Store result
        let mut result_array = [0.0f64; 4];
        _mm256_store_pd(result_array.as_mut_ptr() as *mut f64, result);

        ProcessResult {
            data: result_array,
            timestamp: data.timestamp,
        }
    }

    // Real-time performance monitoring
    fn monitor_performance(&self) {
        let start = Instant::now();

        // Execute real-time processing
        let result = unsafe { self.process_data(&self.get_next_data()) };

        let elapsed = start.elapsed();

        // Check if real-time requirements are met
        if elapsed > Duration::from_micros(100) {
            self.handle_deadline_miss(elapsed);
        }

        // Update performance metrics
        self.metrics.record_latency(elapsed);
    }
}

// Real-time performance metrics
struct RealtimeMetrics {
    min_latency: AtomicU64,
    max_latency: AtomicU64,
    avg_latency: AtomicU64,
    deadline_misses: AtomicU64,
}

impl RealtimeMetrics {
    fn record_latency(&self, latency: Duration) {
        let latency_us = latency.as_micros() as u64;

        // Atomically update minimum latency
        self.min_latency.fetch_min(latency_us, Ordering::Relaxed);

        // Atomically update maximum latency
        self.max_latency.fetch_max(latency_us, Ordering::Relaxed);

        // Update average latency (simplified implementation)
        let current_avg = self.avg_latency.load(Ordering::Relaxed);
        let new_avg = (current_avg + latency_us) / 2;
        self.avg_latency.store(new_avg, Ordering::Relaxed);
    }

    fn record_deadline_miss(&self) {
        self.deadline_misses.fetch_add(1, Ordering::Relaxed);
    }
}

// Industrial control real-time scheduler
struct IndustrialRealtimeScheduler {
    // Periodic tasks
    periodic_tasks: Vec<PeriodicTask>,
    // Event-driven tasks
    event_driven_tasks: Vec<EventDrivenTask>,
    // Schedule table
    schedule_table: ScheduleTable,
}

impl IndustrialRealtimeScheduler {
    fn execute_cycle(&mut self) {
        let cycle_start = Instant::now();

        // Execute periodic tasks
        for task in &mut self.periodic_tasks {
            if task.should_execute(cycle_start) {
                task.execute();
            }
        }

        // Execute event-driven tasks
        for task in &mut self.event_driven_tasks {
            if task.has_pending_events() {
                task.execute();
            }
        }

        let cycle_time = cycle_start.elapsed();

        // Check cycle time constraints
        if cycle_time > Duration::from_micros(1000) {
            self.handle_cycle_overrun(cycle_time);
        }
    }
}

// Deterministic memory allocator
struct DeterministicAllocator {
    // Pre-allocated memory pools
    memory_pools: [MemoryPool; 8],
    // Allocation statistics
    allocation_stats: AllocationStats,
}

impl DeterministicAllocator {
    // Deterministic memory allocation
    fn allocate(&mut self, size: usize, alignment: usize) -> *mut u8 {
        // Select appropriate memory pool
        let pool_index = self.select_pool(size, alignment);

        // Allocate from memory pool
        let ptr = self.memory_pools[pool_index].allocate(size, alignment);

        // Record allocation statistics
        self.allocation_stats.record_allocation(size);

        ptr
    }

    // Deterministic memory deallocation
    fn deallocate(&mut self, ptr: *mut u8, size: usize) {
        // Find corresponding memory pool
        let pool_index = self.find_pool_for_pointer(ptr);

        // Deallocate to memory pool
        self.memory_pools[pool_index].deallocate(ptr, size);

        // Record deallocation statistics
        self.allocation_stats.record_deallocation(size);
    }
}

// Low-latency network processing
struct LowLatencyNetwork {
    // Zero-copy reception
    zero_copy_rx: ZeroCopyReceiver,
    // Fast transmission
    fast_tx: FastTransmitter,
    // Network buffer pool
    network_buffers: NetworkBufferPool,
}

impl LowLatencyNetwork {
    // Zero-copy data reception
    async fn receive_data(&self) -> Result<NetworkPacket> {
        // Use DMA direct memory access
        let packet = self.zero_copy_rx.receive().await?;

        // Fast header parsing
        let header = self.fast_parse_header(&packet)?;

        Ok(NetworkPacket { header, data: packet })
    }

    // Fast data transmission
    async fn send_data(&self, data: &[u8]) -> Result<()> {
        // Use zero-copy transmission
        self.fast_tx.send_zero_copy(data).await?;

        Ok(())
    }
}

// Real-time risk engine
struct RealtimeRiskEngine {
    // Rule engine
    rule_engine: RuleEngine,
    // Risk assessment
    risk_assessor: RiskAssessor,
    // Decision engine
    decision_engine: DecisionEngine,
}

impl RealtimeRiskEngine {
    // Real-time risk assessment
    #[inline(always)]
    fn assess_risk(&self, transaction: &Transaction) -> RiskAssessment {
        // Parallel execution of multiple risk assessments
        let market_risk = self.risk_assessor.assess_market_risk(transaction);
        let credit_risk = self.risk_assessor.assess_credit_risk(transaction);
        let liquidity_risk = self.risk_assessor.assess_liquidity_risk(transaction);

        // Comprehensive risk assessment
        let overall_risk = self.combine_risks(market_risk, credit_risk, liquidity_risk);

        // Real-time decision making
        let decision = self.decision_engine.make_decision(overall_risk);

        RiskAssessment {
            overall_risk,
            decision,
            timestamp: Instant::now(),
        }
    }
}

// FPGA-accelerated real-time processing
struct FPGARealtimeAccelerator {
    // FPGA device
    fpga_device: FPGADevice,
    // Acceleration algorithms
    acceleration_algorithms: Vec<FPGAAlgorithm>,
}

impl FPGARealtimeAccelerator {
    // Configure FPGA acceleration
    fn configure_fpga(&self, algorithm: FPGAAlgorithm) -> Result<()> {
        // Load FPGA bitstream
        self.fpga_device.load_bitstream(algorithm.bitstream)?;

        // Configure FPGA parameters
        self.fpga_device.configure_parameters(algorithm.parameters)?;

        Ok(())
    }

    // FPGA-accelerated processing
    fn accelerate_processing(&self, data: &[u8]) -> Result<Vec<u8>> {
        // Transfer data to FPGA
        self.fpga_device.transfer_data(data)?;

        // Start FPGA processing
        self.fpga_device.start_processing()?;

        // Wait for processing completion
        self.fpga_device.wait_for_completion()?;

        // Read processing result
        let result = self.fpga_device.read_result()?;

        Ok(result)
    }
}

// Quantum real-time computing
struct QuantumRealtimeComputer {
    // Quantum processor
    quantum_processor: QuantumProcessor,
    // Quantum algorithms
    quantum_algorithms: Vec<QuantumAlgorithm>,
}

impl QuantumRealtimeComputer {
    // Quantum-accelerated real-time computing
    fn quantum_accelerate(&self, problem: RealtimeProblem) -> Result<QuantumSolution> {
        // Convert problem to quantum form
        let quantum_problem = self.convert_to_quantum_form(problem)?;

        // Execute quantum algorithm
        let quantum_result = self.quantum_processor.execute_algorithm(quantum_problem)?;

        // Convert result back to classical form
        let classical_solution = self.convert_to_classical_form(quantum_result)?;

        Ok(classical_solution)
    }
}

aws s3 mb [DESTINATION_BUCKET] --region us-east-1

aws s3 sync [SOURCE_BUCKET] [DESTINATION_BUCKET]

aws s3 ls [SOURCE_BUCKET] --recursive --human-readable --summarize

aws s3 ls [DESTINATION_BUCKET] --recursive --human-readable --summarize