題目：

給出一個(gè) 32 位的有符號整數(shù)，你需要將這個(gè)整數(shù)中每位上的數(shù)字進(jìn)行反轉(zhuǎn)。

示例 1:

輸入: 123

輸出: 321

示例 2:

輸入: -123

輸出: -321

示例 3:

輸入: 120

輸出: 21

注意:

假設(shè)我們的環(huán)境只能存儲(chǔ)得下 32 位的有符號整數(shù)，則其數(shù)值范圍為 。請根據(jù)這個(gè)假設(shè)，如果反轉(zhuǎn)后整數(shù)溢出那么就返回 0。

解題思路：1.實(shí)現(xiàn)數(shù)據(jù)的反轉(zhuǎn)

如果是正數(shù)：

tra = 0while x != 0:n2 = x%10x = x //10tra = tra*10 + n2

如果是負(fù)數(shù)就abs()一下這個(gè)數(shù)

2.溢出判定

給出范圍[−2^31, 2^31 − 1]

則輸出的結(jié)果tra就必須滿足這個(gè)范圍.

代碼：

class Solution(object): def reverse(self, x): base = 1 for i in range(31): base = base * 2 two_Max = base - 1 two_Min = -base tra = 0 if x < 0: x = abs(x) while x != 0: n2 = x % 10 if tra > abs(two_Min) // 10 or (tra == abs(two_Min) // 10 and n2 < -8): return 0 x = x // 10 tra = tra * 10 + n2 return -tra else: while x != 0: n2 = x % 10 if tra > two_Max//10 or (tra == two_Max and n2 > 7 ): return 0 x = x // 10 tra = tra * 10 + n2 return tra

補(bǔ)充：python實(shí)現(xiàn)數(shù)字反轉(zhuǎn)_python 數(shù)字怎么反轉(zhuǎn)

每次寫 Python 都會(huì)忘記該怎么寫，最后只能去 Stack Overflow 查？我也一樣。時(shí)間一長，這讓人厭倦。

這15個(gè) Python 技巧和竅門，可以幫你提高效率1. 交換值

x, y = 1, 2 print(x, y) x, y = y, x print(x, y)2. 字符串列表合并為一個(gè)字符串

sentence_list = ['my', 'name', 'is', 'George'] sentence_string = ' '.join(sentence_list) print(sentence_string)3. 將字符串拆分為子字符串列表

sentence_string = 'my name is George' sentence_string.split() print(sentence_string)4. 通過數(shù)字填充初始化列表

[0]*1000 # List of 1000 zeros [8.2]*1000 # List of 1000 8.2’s5. 字典合并

x = {’a’: 1, ’b’: 2} y = {’b’: 3, ’c’: 4} z = {**x, **y}6. 反轉(zhuǎn)字符串

name = 'George' name[::-1] 7. 從函數(shù)返回多個(gè)值

def get_a_string(): a = 'George' b = 'is' c = 'cool' return a, b, c sentence = get_a_string() (a, b, c) = sentence8. 列表解析式

a = [1, 2, 3] b = [num*2 for num in a] # Create a new list by multiplying each element in a by 29. 遍歷字典

m = {’a’: 1, ’b’: 2, ’c’: 3, ’d’: 4} for key, value in m.items(): print(’{0}: {1}’.format(key, value))10. 同時(shí)遍歷列表的索引和值

m = [’a’, ’b’, ’c’, ’d’] for index, value in enumerate(m): print(’{0}: {1}’.format(index, value))11. 初始化空容器

a_list = list() a_dict = dict() a_map = map() a_set = set()12. 刪除字符串兩端的無用字符

name = ' George ' name_2 = 'George///' name.strip() # prints 'George' name_2.strip('/') # prints 'George'13. 列表中出現(xiàn)最多的元素

test = [1, 2, 3, 4, 2, 2, 3, 1, 4, 4, 4] print(max(set(test), key = test.count))14. 檢查對象的內(nèi)存使用情況

import sys x = 1 print(sys.getsizeof(x))15. 將 dict 轉(zhuǎn)換為 XML

from xml.etree.ElementTree import Element def dict_to_xml(tag, d): ’’’ Turn a simple dict of key/value pairs into XML ’’’ elem = Element(tag) for key, val in d.items(): child = Element(key) child.text = str(val) elem.append(child) return elem

以上為個(gè)人經(jīng)驗(yàn)，希望能給大家一個(gè)參考，也希望大家多多支持好吧啦網(wǎng)。如有錯(cuò)誤或未考慮完全的地方，望不吝賜教。