0x81's blog

By 0x81, history, 5 weeks ago,

This https://mirror.codeforces.com/contest/1956/submission/256474898 solution consumes at least (2 * n + 1) * sizeof(int) bytes, on the test #4 the memory usage must be at least 1_600_004 bytes instead of 56 KB.

• +1

By 0x81, history, 10 months ago,

https://mirror.codeforces.com/contest/1846/submission/215981788

1. how to type capital letters?
2. if you've seen this approach before, post links in the comments.
• -4

By 0x81, history, 12 months ago, translation,

The code (Ruby) below is a solution for https://leetcode.com/problems/uncrossed-lines/

Note: In Ruby Array#shift is O(1)

The trick is on the lines 3-4:

def max_uncrossed_lines a, b
# These two lines
c = a.to_set & b.to_set
a, b = *[a, b].map! { | v | v.filter { c === _1 } }
s = 0
while !a.empty? && a.first == b.first
a.shift
b.shift
s += 1
end
while !a.empty? && a.last == b.last
a.pop
b.pop
s += 1
end
r0, r1 = *Array.new(2) { [0] * (b.size + 1) }
for x in a
for y, j in b.each_with_index
r1[j + 1] = (x == y) ?
1 + r0[j] :
[r0[j + 1], r1[j]].max
end
r0, r1 = r1, r0
end
s + r0.last
end

• -2