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建筑企业资质查询网站,深圳学校网站建设,张家港建设局网站,网络服务提供者收集和使用个人信息应当符合的条件有theme: github highlight: an-old-hope 查看本地官方文档 安装rust后运行 rustup doc查看The Standard Library即可获取标准库内容 std::connections::VecDeque定义 队列是遵循先入先出规则的线性数据结构#xff0c;在内存中不一定连续 VecDeque定义#xff1a;可增长… theme: github highlight: an-old-hope 查看本地官方文档 安装rust后运行 rustup doc查看The Standard Library即可获取标准库内容 std::connections::VecDeque定义 队列是遵循先入先出规则的线性数据结构在内存中不一定连续 VecDeque定义可增长的环形缓冲区实现的双端队列 pub struct VecDequeT, A: Allocator Global {// 队列头部在内部缓冲区中的索引位置head: usize,// 当前队列中的元素数量len: usize,// 管理内存分配和释放确保有足够的空间来存储队列中的元素buf: RawVecT, A, }方法 with_capacity用于创建一个具有指定初始容量的VecDeque use std::collections::VecDeque;fn main() {let deque VecDeque::from([1, 2, 3]);if let Some(element) deque.get(1) {println!(Element at index 1: {}, element);// Element at index 1: 2} }get获取指定索引位置的元素的不可变引用 use std::collections::VecDeque;fn main() {let deque VecDeque::from([1, 2, 3]);if let Some(element) deque.get(1) {println!(Element at index 1: {}, element);// Element at index 1: 2} }get_mut获取指定索引位置的元素的可变引用 use std::collections::VecDeque;fn main() {let mut deque VecDeque::from([1, 2, 3]);if let Some(element) deque.get_mut(1) {*element 4;}println!(Modified deque: {:?}, deque);// Modified deque: [1, 4, 3] }swap交换VecDeque中两个指定索引位置的元素 use std::collections::VecDeque;fn main() {let mut deque VecDeque::from([1, 2, 3]);deque.swap(0, 2);println!(Swapped deque: {:?}, deque);// Swapped deque: [3, 2, 1] }capacity返回VecDeque当前的容量 use std::collections::VecDeque;fn main() {let mut deque VecDeque::with_capacity(5);println!(Initial capacity: {}, deque.capacity());// Initial capacity: 5deque.push_back(1);println!(Capacity after adding an element: {}, deque.capacity());// Capacity after adding an element: 5 }reserve_exact精确地预留足够的空间以容纳指定数量的额外元素 use std::collections::VecDeque;fn main() {let mut deque VecDeque::new();deque.reserve_exact(3);println!(Capacity after reserve_exact: {}, deque.capacity());// Capacity after reserve_exact: 3deque.push_back(1);deque.push_back(2);deque.push_back(3); }reserve预留足够的空间以容纳指定数量的额外元素空间不够自动增长 use std::collections::VecDeque;fn main() {let mut deque VecDeque::new();deque.reserve(5);println!(Capacity after reserve: {}, deque.capacity());// Capacity after reserve: 5deque.push_back(1);deque.push_back(2);deque.push_back(3);deque.push_back(4);deque.push_back(5);deque.push_back(6);println!(Capacity after reserve: {}, deque.capacity());// Capacity after reserve: 10 }try_reserve_exact尝试精确地预留足够的空间以容纳指定数量的额外元素如果预留成功则返回Ok(())否则返回错误 use std::collections::VecDeque;fn main() {let mut deque VecDeque::new();if let Ok(()) deque.try_reserve_exact(3) {println!(Reserved successfully. Capacity: {}, deque.capacity());// Reserved successfully. Capacity: 3} else {println!(Reserve failed.);}deque.push_back(1);deque.push_back(2);deque.push_back(3);deque.push_back(4);println!(Reserved successfully. Capacity: {}, deque.capacity());// Reserved successfully. Capacity: 6 }try_reserve尝试预留足够的空间以容纳指定数量的额外元素如果预留成功则返回Ok(())否则返回错误 use std::collections::VecDeque;fn main() {let mut deque VecDeque::new();if let Ok(()) deque.try_reserve(3) {println!(Reserved successfully. Capacity: {}, deque.capacity());// Reserved successfully. Capacity: 4} else {println!(Reserve failed.);}deque.push_back(1);deque.push_back(2);deque.push_back(3);deque.push_back(4); }shrink_to_fit将VecDeque的容量收缩到与当前元素数量相同 use std::collections::VecDeque;fn main() {let mut deque VecDeque::with_capacity(10);deque.push_back(1);deque.push_back(2);deque.push_back(3);deque.shrink_to_fit();println!(Capacity after shrink_to_fit: {}, deque.capacity());// Capacity after shrink_to_fit: 3 }shrink_to将VecDeque的容量收缩到指定大小 use std::collections::VecDeque;fn main() {let mut deque VecDeque::with_capacity(10);deque.push_back(1);deque.push_back(2);deque.push_back(3);deque.shrink_to(5);println!(Capacity after shrink_to: {}, deque.capacity());// Capacity after shrink_to: 5 }truncate将VecDeque截断到指定长度 use std::collections::VecDeque;fn main() {let mut deque VecDeque::from([1, 2, 3, 4, 5]);deque.truncate(3);println!(Truncated deque: {:?}, deque);// Truncated deque: [1, 2, 3] }iter返回一个不可变的迭代器用于遍历VecDeque中的元素 use std::collections::VecDeque;fn main() {let deque VecDeque::from([1, 2, 3]);for element in deque.iter() {println!(Element: {}, element);}// Element: 1// Element: 2// Element: 3 }iter_mut返回一个可变的迭代器允许在遍历过程中修改VecDeque中的元素 use std::collections::VecDeque;fn main() {let mut deque VecDeque::from([1, 2, 3]);for element in deque.iter_mut() {*element * 2;}println!(Modified deque: {:?}, deque);// Modified deque: [2, 4, 6] }as_slice将VecDeque分成不可变的切片 use std::collections::VecDeque;fn main() {let deque VecDeque::from([1, 2, 3, 4, 5]);let (front_slice, back_slice) deque.as_slices();println!(Front slice: {:?}, front_slice);// Front slice: [1, 2, 3, 4, 5]println!(Back slice: {:?}, back_slice);// Back slice: [] }as_mut_slices将VecDeque分成可变的切片 use std::collections::VecDeque;fn main() {let mut deque VecDeque::from([1, 2, 3, 4, 5]);let (front_slice, back_slice) deque.as_mut_slices();for element in front_slice {*element * 2;}for element in back_slice {*element * 3;}println!(Modified deque: {:?}, deque);// Modified deque: [2, 4, 6, 8, 10] }len返回VecDeque中元素的数量 use std::collections::VecDeque;fn main() {let deque VecDeque::from([1, 2, 3]);println!(Length of deque: {}, deque.len());// Length of deque: 3 }is_empty判断VecDeque是否为空 use std::collections::VecDeque;fn main() {let deque:VecDequei32 VecDeque::new();println!(Is deque empty? {}, deque.is_empty());// Is deque empty? truelet deque2 VecDeque::from([1]);println!(Is deque2 empty? {}, deque2.is_empty());// Is deque2 empty? false }range返回一个指定范围内的不可变迭代器 use std::collections::VecDeque;fn main() {let deque VecDeque::from([1, 2, 3, 4, 5]);for element in deque.range(1..3) {println!(Element: {}, element);// Element: 2// Element: 3} }range_mut返回一个指定范围内的可变迭代器 use std::collections::VecDeque;fn main() {let mut deque VecDeque::from([1, 2, 3, 4, 5]);for element in deque.range_mut(1..3) {*element * 2;}println!(Modified deque: {:?}, deque);// Modified deque: [1, 4, 6, 4, 5] }drain移除并返回一个迭代器用于遍历被移除的元素 use std::collections::VecDeque;fn main() {let mut deque VecDeque::from([1, 2, 3, 4, 5]);let drained deque.drain(1..3).collect::Veci32();println!(Drained elements: {:?}, drained);// Drained elements: [2, 3]println!(Remaining deque: {:?}, deque);// Remaining deque: [1, 4, 5] }clear清空VecDeque移除所有元素 use std::collections::VecDeque;fn main() {let mut deque VecDeque::from([1, 2, 3]);println!(Before clearing: {:?}, deque);// Before clearing: [1, 2, 3]deque.clear();println!(After clearing: {:?}, deque);// After clearing: [] }contains判断VecDeque中是否包含特定元素 use std::collections::VecDeque;fn main() {let deque VecDeque::from([1, 2, 3]);println!(Does deque contain 2? {}, deque.contains(2));// Does deque contain 2? trueprintln!(Does deque contain 4? {}, deque.contains(4));// Does deque contain 4? false }front返回VecDeque头部元素的不可变引用如果为空则返回None use std::collections::VecDeque;fn main() {let deque VecDeque::from([1, 2, 3]);if let Some(element) deque.front() {println!(Front element: {}, element);// Front element: 1} }front_mut返回VecDeque头部元素的可变引用如果为空则返回None use std::collections::VecDeque;fn main() {let mut deque VecDeque::from([1, 2, 3]);if let Some(element) deque.front_mut() {*element 4;}println!(Modified deque: {:?}, deque);// Modified deque: [4, 2, 3] }back返回VecDeque尾部元素的不可变引用如果为空则返回None use std::collections::VecDeque;fn main() {let deque VecDeque::from([1, 2, 3]);if let Some(element) deque.back() {println!(Back element: {}, element);// Back element: 3} }back_mut返回VecDeque尾部元素的可变引用如果为空则返回None use std::collections::VecDeque;fn main() {let mut deque VecDeque::from([1, 2, 3]);if let Some(element) deque.back_mut() {*element 4;}println!(Modified deque: {:?}, deque);// Modified deque: [1, 2, 4] }pop_front移除并返回VecDeque头部元素如果为空则返回None use std::collections::VecDeque;fn main() {let mut deque VecDeque::from([1, 2, 3]);if let Some(element) deque.pop_front() {println!(Popped element: {}, element);// Popped element: 1}println!(Remaining deque: {:?}, deque);// Remaining deque: [2, 3] }pop_back移除并返回VecDeque尾部元素如果为空则返回None use std::collections::VecDeque;fn main() {let mut deque VecDeque::from([1, 2, 3]);if let Some(element) deque.pop_back() {println!(Popped element: {}, element);// Popped element: 3}println!(Remaining deque: {:?}, deque);// Remaining deque: [1, 2] }push_front在VecDeque头部插入一个元素 use std::collections::VecDeque;fn main() {let mut deque VecDeque::new();deque.push_front(1);deque.push_front(2);println!(Modified deque: {:?}, deque);// Modified deque: [2, 1] }push_back在VecDeque尾部插入一个元素 use std::collections::VecDeque;fn main() {let mut deque VecDeque::new();deque.push_back(1);deque.push_back(2);println!(Modified deque: {:?}, deque);// Modified deque: [1, 2] }swap_remove_front移除并返回VecDeque头部开始的元素索引同时用其后的第一个元素替换它避免移动其后的所有元素如果为空则返回None use std::collections::VecDeque;fn main() {let mut deque VecDeque::from([1, 2, 3, 4]);if let Some(element) deque.swap_remove_front(2) {println!(Swapped and removed element: {}, element);// Swapped and removed element: 3}println!(Remaining deque: {:?}, deque);// Remaining deque: [2, 1, 4] }swap_remove_back移除并返回VecDeque尾部开始的元素索引同时用前一个元素替换它避免移动前面的所有元素如果为空则返回None use std::collections::VecDeque;fn main() {let mut deque VecDeque::from([1, 2, 3, 4]);if let Some(element) deque.swap_remove_back(2) {println!(Swapped and removed element from back: {}, element);// Swapped and removed element from back: 3}println!(Remaining deque: {:?}, deque);// Remaining deque: [1, 2, 4] }insert在指定索引位置插入一个元素。如果索引超出范围会导致程序 panic元素为[1,2,3]时容量为3插入索引1不改变容量插入4时由于索引是连续的会开辟原队列的两倍容量6后续插入索引5可以成功如果直接插入5索引不连续不会开辟新空间会panic use std::collections::VecDeque;fn main() {let mut deque VecDeque::from([1, 2, 3]);println!(deque capacity: {}, deque.capacity());// deque capacity: 3deque.insert(1, 9);// deque.insert(4, 5); // 这一行存在以下操作成功不存在 panic!deque.insert(5, 6); // panic!println!(deque capacity: {}, deque.capacity());// deque capacity: 6println!(After insertion: {:?}, deque);// After insertion: [1, 9, 2, 4, 3, 6]println!(deque capacity: {}, deque.capacity());// deque capacity: 6 }remove移除指定索引位置的元素并返回该元素。如果索引超出范围会导致程序 panic use std::collections::VecDeque;fn main() {let mut deque VecDeque::from([1, 2, 3]);if let Some(element) deque.remove(1) {println!(Removed element: {}, element);// Removed element: 2}println!(Remaining deque: {:?}, deque);// Remaining deque: [1, 3] }split_off在指定索引位置将VecDeque分割成两个返回从指定索引开始的后半部分 use std::collections::VecDeque;fn main() {let mut deque VecDeque::from([1, 2, 3, 4, 5]);let deque2 deque.split_off(2);println!({:?}, deque2);// [3, 4, 5] }append将另一个VecDeque的所有元素追加到当前VecDeque的末尾 use std::collections::VecDeque;fn main() {let mut deque1 VecDeque::from([1, 2, 3]);let mut deque2 VecDeque::from([4, 5, 6]);deque1.append(mut deque2);println!(Appended deque: {:?}, deque1);// Appended deque: [1, 2, 3, 4, 5, 6] }retain保留满足给定谓词的元素移除不满足的元素 use std::collections::VecDeque;fn main() {let mut deque VecDeque::from([1, 2, 3, 4, 5]);deque.retain(|x| x % 2 0);println!(After retain: {:?}, deque);// After retain: [2, 4] }retain_mut与retain类似但可以对元素进行可变操作 use std::collections::VecDeque;fn main() {let mut deque VecDeque::from([1, 2, 3, 4, 5]);deque.retain_mut(|x| {*x * 2;*x % 3 0});println!(After retain_mut: {:?}, deque);// After retain_mut: [6] }resize_with调整VecDeque的大小到指定长度使用给定的函数生成新元素填充额外的空间或者截断多余的元素 use std::collections::VecDeque;fn main() {let mut deque VecDeque::from([1, 2]);deque.resize_with(5, || 0);println!(Resized deque: {:?}, deque);// Resized deque: [1, 2, 0, 0, 0] }make_contiguous尝试使VecDeque在内存中连续存储可能会导致重新分配内存 use std::collections::VecDeque;fn main() {let mut deque VecDeque::from([1, 2, 3]);deque.make_contiguous();println!(After make_contiguous: {:?}, deque);// After make_contiguous: [1, 2, 3] }rotate_left将VecDeque向左旋转指定的步数 use std::collections::VecDeque;fn main() {let mut deque VecDeque::from([1, 2, 3, 4, 5]);deque.rotate_left(2);println!(After rotate_left: {:?}, deque);// After rotate_left: [3, 4, 5, 1, 2] }rotate_right将VecDeque向右旋转指定的步数 use std::collections::VecDeque;fn main() {let mut deque VecDeque::from([1, 2, 3, 4, 5]);deque.rotate_right(2);println!(After rotate_right: {:?}, deque);// After rotate_right: [4, 5, 1, 2, 3] }binary_search在已排序的VecDeque中进行二分查找指定元素返回一个Result类型表示查找结果。如果找到元素返回Ok(index)默认最后一个结果如果未找到返回Err()在未排序的队列进行查找会返回unspecified这个结果没有意义 当查找的元素不存在时返回查找元素应当插入位置有序队列位置的索引 当查找的元素存在时返回最后一个匹配的元素 use std::collections::VecDeque;fn main() {let deque VecDeque::from([1, 2, 3, 3, 4, 5]);let result deque.binary_search(3);println!({:?}, result);// Ok(3)// 有序且不存在let deque VecDeque::from([3, 3, 3, 3, 3, 4, 4, 7, 8]);let result deque.binary_search(5);println!({:?}, result);// Err(7)// 有序且存在let deque VecDeque::from([3, 3, 3, 3, 3, 4, 4, 7, 8]);let result deque.binary_search(3);println!({:?}, result);// Ok(4)// 注意以下结果没有意义// 无序且不存在let deque VecDeque::from([3, 9, 3, 3, 8, 4, 3, 7, 3]);let result deque.binary_search(5);println!({:?}, result);// Err(4)// 无序且存在let deque VecDeque::from([3, 9, 3, 3, 8, 4, 3, 7, 3]);let result deque.binary_search(3);println!({:?}, result);// Ok(2) }binary_search_by使用自定义的比较函数在已排序的VecDeque中进行二分查找 use std::collections::VecDeque;fn main() {let deque VecDeque::from([1, 2, 3, 3, 4, 6]);// 找到最后一个等于3的元素索引let result deque.binary_search_by(|x| x.cmp(3));println!({:?}, result);// Ok(3)// 找到最后一个等于5de的元素索引,不存在返回应当插入位置的索引let result deque.binary_search_by(|x| x.cmp(5));println!({:?}, result);// Err(5) }binary_search_by_key如果队列是以元组键的顺序排序的使用自定义的键提取函数在已排序的VecDeque中进行二分查找 use std::collections::VecDeque;fn main() {let deque VecDeque::from([(0, 0),(2, 1),(4, 1),(5, 1),(3, 1),(1, 2),(2, 3),(4, 5),(5, 8),(3, 13),(1, 21),(2, 34),(4, 55),]);// 按元组第二个键值排序let result deque.binary_search_by_key(13, |(a, b)| b);println!({:?}, result);// Ok(9) }partition_point在已排序的VecDeque中找到满足给定谓词的元素的分界点。即返回第一个不满足谓词的元素的索引 use std::collections::VecDeque;fn main() {let deque: VecDequei32 VecDeque::from([1, 2, 3, 3, 5, 6, 7]);// 按小于5的元素划分返回第一个大于等于5的索引let result deque.partition_point(|x| x 5);println!({:?}, result);// 4 }