{"draftJsState":{"blocks":[{"data":{},"depth":0,"entityRanges":[],"inlineStyleRanges":[{"length":65,"offset":0,"style":"ITALIC"}],"text":"Или как заставить биты двигаться и сделать за нас грязную работу.","type":"unstyled","key":"89eg4"},{"data":{},"depth":0,"entityRanges":[],"inlineStyleRanges":[{"length":48,"offset":168,"style":"BOLD"}],"text":"Когда мы слышим \"битовые сдвиги\", в голове сразу всплывают ассемблер, страшные бинарные числа и программисты в чёрных худи, шепчущие n << 1 при луне. Но на самом деле, битовые сдвиги — это мощный и удобный инструмент, который часто используется в задачах на собеседованиях, особенно там, где нужна скорость, компактность и чуть-чуть магии.","type":"unstyled","key":"4jk7a"},{"data":{},"depth":0,"entityRanges":[],"inlineStyleRanges":[],"text":"В этой статье мы:","type":"unstyled","key":"36rm"},{"data":{},"depth":0,"entityRanges":[],"inlineStyleRanges":[],"text":"разберём операторы << и >>;","type":"unordered-list-item","key":"9bbp7"},{"data":{},"depth":0,"entityRanges":[],"inlineStyleRanges":[],"text":"увидим, как работают сдвиги на пальцах;","type":"unordered-list-item","key":"csq4i"},{"data":{},"depth":0,"entityRanges":[],"inlineStyleRanges":[],"text":"порешаем задачи (и для новичков, и для тех, кто любит \"хардкор\").","type":"unordered-list-item","key":"an2pb"},{"data":{},"depth":0,"entityRanges":[],"inlineStyleRanges":[],"text":"\uD83E\uDDEE Основы: что такое побитовые сдвиги?","type":"header-two","key":"d259n"},{"data":{},"depth":0,"entityRanges":[],"inlineStyleRanges":[{"length":5,"offset":57,"style":"BOLD"},{"length":6,"offset":65,"style":"BOLD"}],"text":"Python (и другие языки) позволяет вам двигать биты числа влево и вправо:","type":"unstyled","key":"5r3vk"},{"data":{},"depth":0,"entityRanges":[],"inlineStyleRanges":[],"text":"x << n — сдвиг влево на n бит. Умножает x на 2^n.","type":"unordered-list-item","key":"6c2ad"},{"data":{},"depth":0,"entityRanges":[],"inlineStyleRanges":[],"text":"x >> n — сдвиг вправо на n бит. Делит x на 2^n (целочисленно).","type":"unordered-list-item","key":"7dkm0"},{"data":{},"depth":0,"entityRanges":[],"inlineStyleRanges":[],"text":"Пример 1: Простое умножение и деление","type":"header-three","key":"40u9u"},{"data":{},"depth":0,"entityRanges":[],"inlineStyleRanges":[],"text":"x = 4\nprint(x << 1) # Сдвигаем влево на 1 (4 * 2 = 8)\nprint(x >> 1) # Сдвигаем вправо на 1 (4 // 2 = 2)","type":"unstyled","key":"2tk2"},{"data":{},"depth":0,"entityRanges":[],"inlineStyleRanges":[{"length":12,"offset":0,"style":"BOLD"}],"text":"Комментарии:","type":"unstyled","key":"2ihi2"},{"data":{},"depth":0,"entityRanges":[],"inlineStyleRanges":[],"text":"4 в двоичной — 100","type":"unordered-list-item","key":"3bh0e"},{"data":{},"depth":0,"entityRanges":[],"inlineStyleRanges":[],"text":"4 << 1 → 1000 → это 8","type":"unordered-list-item","key":"4so5e"},{"data":{},"depth":0,"entityRanges":[],"inlineStyleRanges":[],"text":"4 >> 1 → 10 → это 2","type":"unordered-list-item","key":"8mkn9"},{"data":{},"depth":0,"entityRanges":[],"inlineStyleRanges":[],"text":"\uD83D\uDCCC А теперь задачки. От простого к божественному.","type":"header-two","key":"ei8v"},{"data":{},"depth":0,"entityRanges":[],"inlineStyleRanges":[],"text":"✅ Задача 1: Проверить, чётное ли число, без if и %","type":"header-three","key":"hm7"},{"data":{},"depth":0,"entityRanges":[],"inlineStyleRanges":[],"text":"def is_even(n):\n return (n & 1) == 0","type":"unstyled","key":"g4a8"},{"data":{},"depth":0,"entityRanges":[],"inlineStyleRanges":[{"length":11,"offset":0,"style":"BOLD"}],"text":"Объяснение:","type":"unstyled","key":"cph8d"},{"data":{},"depth":0,"entityRanges":[],"inlineStyleRanges":[{"length":13,"offset":16,"style":"BOLD"}],"text":"n & 1 проверяет последний бит числа.","type":"unordered-list-item","key":"ervd0"},{"data":{},"depth":0,"entityRanges":[],"inlineStyleRanges":[],"text":"Если он 1 — число нечётное. Если 0 — чётное.","type":"unordered-list-item","key":"8ricn"},{"data":{},"depth":0,"entityRanges":[],"inlineStyleRanges":[],"text":"print(is_even(10)) # True\nprint(is_even(7)) # False","type":"unstyled","key":"gc4k"},{"data":{},"depth":0,"entityRanges":[],"inlineStyleRanges":[],"text":"✅ Задача 2: Умножить на 8 без *","type":"header-three","key":"7g6dn"},{"data":{},"depth":0,"entityRanges":[],"inlineStyleRanges":[],"text":"def multiply_by_eight(n):\n return n << 3 # 2^3 = 8","type":"unstyled","key":"tc0"},{"data":{},"depth":0,"entityRanges":[],"inlineStyleRanges":[{"length":20,"offset":0,"style":"BOLD"}],"text":"Почему это работает:","type":"unstyled","key":"ekr0t"},{"data":{},"depth":0,"entityRanges":[],"inlineStyleRanges":[],"text":"Сдвиг влево на 3 позиции = умножение на 2³ = 8","type":"unordered-list-item","key":"fvcqq"},{"data":{},"depth":0,"entityRanges":[],"inlineStyleRanges":[],"text":"print(multiply_by_eight(5)) # 40","type":"unstyled","key":"d6uhl"},{"data":{},"depth":0,"entityRanges":[],"inlineStyleRanges":[],"text":"✅ Задача 3: Найти уникальное число в списке, где остальные дублируются","type":"header-three","key":"at08"},{"data":{},"depth":0,"entityRanges":[],"inlineStyleRanges":[],"text":"def find_unique(nums):\n result = 0\n for num in nums:\n result ^= num\n return result","type":"unstyled","key":"cov18"},{"data":{},"depth":0,"entityRanges":[],"inlineStyleRanges":[{"length":15,"offset":0,"style":"BOLD"}],"text":"Что происходит:","type":"unstyled","key":"95anq"},{"data":{},"depth":0,"entityRanges":[],"inlineStyleRanges":[],"text":"XOR (^) — суперспособность.","type":"unordered-list-item","key":"dh08h"},{"data":{},"depth":0,"entityRanges":[],"inlineStyleRanges":[],"text":"a ^ a = 0, a ^ 0 = a","type":"unordered-list-item","key":"41n2o"},{"data":{},"depth":0,"entityRanges":[],"inlineStyleRanges":[],"text":"Все дубликаты \"взаимоуничтожаются\", остаётся уникальный элемент.","type":"unordered-list-item","key":"55mpt"},{"data":{},"depth":0,"entityRanges":[],"inlineStyleRanges":[],"text":"print(find_unique([2, 3, 2, 4, 4])) # 3","type":"unstyled","key":"66g40"},{"data":{},"depth":0,"entityRanges":[],"inlineStyleRanges":[],"text":"✅ Задача 4: Подсчитать количество установленных битов (единичек)","type":"header-three","key":"dq4i9"},{"data":{},"depth":0,"entityRanges":[],"inlineStyleRanges":[],"text":"def count_bits(n):\n count = 0\n while n:\n count += n & 1\n n >>= 1\n return count","type":"unstyled","key":"8818m"},{"data":{},"depth":0,"entityRanges":[],"inlineStyleRanges":[{"length":10,"offset":0,"style":"BOLD"}],"text":"Пояснение:","type":"unstyled","key":"4g2rs"},{"data":{},"depth":0,"entityRanges":[],"inlineStyleRanges":[],"text":"n & 1 проверяет, установлен ли младший бит.","type":"unordered-list-item","key":"71e7e"},{"data":{},"depth":0,"entityRanges":[],"inlineStyleRanges":[],"text":"n >>= 1 сдвигает число вправо (убираем младший бит).","type":"unordered-list-item","key":"8ktid"},{"data":{},"depth":0,"entityRanges":[],"inlineStyleRanges":[],"text":"Повторяем, пока не обнулим всё число.","type":"unordered-list-item","key":"5t52r"},{"data":{},"depth":0,"entityRanges":[],"inlineStyleRanges":[],"text":"print(count_bits(7)) # 3, потому что 111\nprint(count_bits(8)) # 1, потому что 1000","type":"unstyled","key":"cocc4"},{"data":{},"depth":0,"entityRanges":[],"inlineStyleRanges":[],"text":"✅ Задача 5 (профи): Переставить биты в числе в обратном порядке","type":"header-three","key":"224t"},{"data":{},"depth":0,"entityRanges":[],"inlineStyleRanges":[],"text":"def reverse_bits(n, bits=32):\n result = 0\n for i in range(bits):\n result <<= 1\n result |= (n >> i) & 1\n return result","type":"unstyled","key":"6a2bt"},{"data":{},"depth":0,"entityRanges":[],"inlineStyleRanges":[{"length":15,"offset":0,"style":"BOLD"}],"text":"Что происходит:","type":"unstyled","key":"ad5vf"},{"data":{},"depth":0,"entityRanges":[],"inlineStyleRanges":[],"text":"Мы берём каждый бит n, начиная с младшего (справа).","type":"unordered-list-item","key":"4hq9t"},{"data":{},"depth":0,"entityRanges":[],"inlineStyleRanges":[],"text":"Кладём его в result слева.","type":"unordered-list-item","key":"d4iiu"},{"data":{},"depth":0,"entityRanges":[],"inlineStyleRanges":[],"text":"Получается \"перевёрнутая\" битовая строка.","type":"unordered-list-item","key":"fihei"},{"data":{},"depth":0,"entityRanges":[],"inlineStyleRanges":[],"text":"print(bin(reverse_bits(0b00000000000000000000000000000101))) # → '0b10100000000000000000000000000000'","type":"unstyled","key":"cc5n5"},{"data":{},"depth":0,"entityRanges":[],"inlineStyleRanges":[],"text":"\uD83D\uDEE0 Зачем вообще это всё?","type":"header-two","key":"9bukl"},{"data":{},"depth":0,"entityRanges":[],"inlineStyleRanges":[],"text":"Побитовые сдвиги и операции:","type":"unstyled","key":"ah2mt"},{"data":{},"depth":0,"entityRanges":[],"inlineStyleRanges":[],"text":"Ускоряют выполнение (умножения и деления — медленные операции).","type":"unordered-list-item","key":"7a3bo"},{"data":{},"depth":0,"entityRanges":[],"inlineStyleRanges":[{"length":47,"offset":14,"style":"BOLD"}],"text":"Часто нужны в работе с флагами, битовыми масками, компрессией.","type":"unordered-list-item","key":"9ucv0"},{"data":{},"depth":0,"entityRanges":[],"inlineStyleRanges":[{"length":46,"offset":19,"style":"BOLD"}],"text":"Важны в задачах по алгоритмам, безопасности, low-level разработке.","type":"unordered-list-item","key":"1vemv"},{"data":{},"depth":0,"entityRanges":[],"inlineStyleRanges":[],"text":"\uD83D\uDE04 Заключение","type":"header-two","key":"b6rvm"},{"data":{},"depth":0,"entityRanges":[],"inlineStyleRanges":[{"length":15,"offset":59,"style":"BOLD"}],"text":"Побитовые сдвиги — это не страшный динозавр из прошлого, а швейцарский нож для оптимизации и решения изящных задач. Они делают код компактнее, быстрее и иногда просто прикольнее.","type":"unstyled","key":"brem8"},{"data":{},"depth":0,"entityRanges":[],"inlineStyleRanges":[{"length":6,"offset":2,"style":"ITALIC"},{"length":31,"offset":90,"style":"BOLD"}],"text":"\uD83D\uDCA1 Совет: если хочешь стать разработчиком, который не боится ни LeetCode, ни продакшена, — учи и практикуй побитовые штуки. Да, иногда тебе кажется, что ты больше электрик, чем программист, но зато как красиво!","type":"unstyled","key":"43g0u"},{"data":{"image":{"id":"6810534befd36779d2353ad8"}},"depth":0,"entityRanges":[],"inlineStyleRanges":[],"text":"","type":"atomic:image","key":"7ra33"},{"data":{},"depth":0,"entityRanges":[],"inlineStyleRanges":[],"text":"","type":"unstyled","key":"5dr9q"},{"data":{},"depth":0,"entityRanges":[],"inlineStyleRanges":[],"text":"","type":"marker","key":"onL7r3I7rLjnHJa23hfz"}],"entityMap":{}},"mentions":[]}