Created
April 24, 2016 13:17
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cpp-like lower_bound, upper_bound in Ruby
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def lowerBound(a, key) | |
lb = -1; ub = a.length | |
while ub - lb > 1 | |
mid = (lb + ub) / 2 | |
if a[mid] >= key | |
ub = mid | |
else | |
lb = mid | |
end | |
end | |
ub | |
end | |
def upperBound(a, key) | |
lb = -1; ub = a.length | |
while ub - lb > 1 | |
mid = (lb + ub) / 2 | |
if a[mid] <= key | |
lb = mid | |
else | |
ub = mid | |
end | |
end | |
ub | |
end |
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def lowerBound(a, key) | |
idx = (0...a.size).bsearch { |i| a[i] >= key } | |
#idx = bsearch_index { |e| e >= key } #Ruby 2.3 and later | |
idx.nil? ? a.size : idx | |
end | |
def upperBound(a, key) | |
idx = (0...a.size).bsearch { |i| a[i] > key } | |
#idx = bsearch_index { |e| e > key } #Ruby 2.3 and later | |
idx.nil? ? a.size : idx | |
end |
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