HTTP 简介

HTTP 简介

HTTP协议是Hyper Text Transfer Protocol（超文本传输协议）的缩写,是用于从万维网（WWW:World Wide Web ）服务器传输超文本到本地浏览器的传送协议。。

HTTP是一个基于TCP/IP通信协议来传递数据（HTML 文件, 图片文件, 查询结果等）。

Given a 2D board and a word, find if the word exists in the grid.

Given an array of non-negative integers, you are initially positioned at the first index of the array.

Given a linked list, return the node where the cycle begins. If there is no cycle, return null.

Given a list of daily temperatures T, return a list such that, for each day in the input, tells you how many days you would have to wait until a warmer temperature. If there is no future day for which this is possible, put 0 instead.

For example, given the list of temperatures T = [73, 74, 75, 71, 69, 72, 76, 73], your output should be [1, 1, 4, 2, 1, 1, 0, 0].

Note: The length of temperatures will be in the range [1, 30000]. Each temperature will be an integer in the range [30, 100].

Given a 2D binary matrix filled with 0’s and 1’s, find the largest square containing only 1’s and return its area.

Given a binary tree, find the lowest common ancestor (LCA) of two given nodes in the tree.

python代码：

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38

import torch
import torch.nn as nn
import matplotlib.pyplot as plt
import imageio

torch.manual_seed(0)

num_samples = 100

x_train = torch.linspace(0, 1, num_samples)
y_train = 0.1 * x_train + 0.2 + torch.randn(num_samples)*0.03

w = torch.randn(1, requires_grad=True)
b = torch.randn(1, requires_grad=True)

criterion = nn.MSELoss()
optimizer = torch.optim.SGD([w,b], lr=0.01)

images = []
num_epochs = 4000
for epoch in range(num_epochs):
    y_pred = w * x_train + b
    loss = criterion(y_pred, y_train)
    optimizer.zero_grad()
    loss.backward()
    if epoch % 100 == 99:
        plt.figure()
        plt.ylim(torch.min(y_train).item(), torch.max(y_train).item())
        plt.scatter(x_train.tolist(), y_train.tolist(), marker='.')
        plt.plot(x_train.tolist(), y_pred.tolist(), color='r', linewidth=2)
        plt.title('Epoch [{}/{}], Loss: {:.6f}, \n Weight: {:.6f}, Bias: {:.6f}'
                  .format(epoch+1, num_epochs, loss.item(), w.item(), b.item()))
        plt.savefig('a.png')
        plt.close()
        images.append(imageio.imread('a.png'))
    optimizer.step()
    
imageio.mimsave('gen.gif', images, duration=0.5)

首先，介绍一下PIL中的基本概念。

PIL中所涉及的基本概念有如下几个：通道（bands）、模式（mode）、尺寸（size）、坐标系统（coordinate system）、调色板（palette）、信息（info）和滤波器（filters）。

那个星夜越过千年
而我绕过半个地球
重新来寻那个你
那个亮尽我的眼的你
一颗流星划过
坠入无边黑暗
你等我一千年
我找你十万里
——《星空》湮夫

Read more »