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Bomb dropping algorithm
...the only way to reduce the hollow rectangle of squares on the
perimeter to 0 is to bomb either the perimeter or to bomb the hollow rectangle of
squares just inside the perimeter. I'll call the perimeter layer 1, and the rectangle inside it layer 2.
An important insight is that there is no point b...
Difference between numpy.array shape (R, 1) and (R,)
...required. For example, given a matrix M , if we want to do numpy.dot(M[:,0], numpy.ones((1, R))) where R is the number of rows (of course, the same issue also occurs column-wise). We will get matrices are not aligned error since M[:,0] is in shape (R,) but numpy.ones((1, R)) is in shape...
LINGO使用指南 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...：
在模型窗口中输入如下代码：
min=2*x1+3*x2;
x1+x2>=350;
x1>=100;
2*x1+x2<=600;
然后点击工具条上的按钮 即可。
例1.2 使用LINGO软件计算6个发点8个收点的最小费用运输问题。产销单位运价如下表。
销地
产地
B...
Convert tuple to list and back
...confused.
– Jimmy
Aug 28 '18 at 19:30
6
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Python and pip, list all versions of a package that's available?
...
170
(update: As of March 2020, many people have reported that yolk, installed via pip install yolk3k...
Regular expression to match numbers with or without commas and decimals in text
...
10 Answers
10
Active
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How to pretty-print a numpy.array without scientific notation and with given precision?
...o set the precision of the output:
import numpy as np
x=np.random.random(10)
print(x)
# [ 0.07837821 0.48002108 0.41274116 0.82993414 0.77610352 0.1023732
# 0.51303098 0.4617183 0.33487207 0.71162095]
np.set_printoptions(precision=3)
print(x)
# [ 0.078 0.48 0.413 0.83 0.776 0.102...
Find MongoDB records where array field is not empty
... the key, you can use:
ME.find({ pictures: { $exists: true, $not: {$size: 0} } })
MongoDB don't use indexes if $size is involved, so here is a better solution:
ME.find({ pictures: { $exists: true, $ne: [] } })
Since MongoDB 2.6 release, you can compare with the operator $gt but could lead to u...
How to sort an array in descending order in Ruby
...Here's what I found out:
#!/usr/bin/ruby
require 'benchmark'
ary = []
1000.times {
ary << {:bar => rand(1000)}
}
n = 500
Benchmark.bm(20) do |x|
x.report("sort") { n.times { ary.sort{ |a,b| b[:bar] <=> a[:bar] } } }
x.report("sort reverse") { n.times {...
How to increase the gap between text and underlining in CSS
...
370
No, but you could go with something like border-bottom: 1px solid #000 and padding-bottom: 3px.
...