Difference between revisions of "Euler problems/161 to 170"
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(Added solution for problem 166) |
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− | == [http://projecteuler.net/index.php?section= |
+ | == [http://projecteuler.net/index.php?section=problems&id=161 Problem 161] == |
Triominoes |
Triominoes |
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</haskell> |
</haskell> |
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− | == [http://projecteuler.net/index.php?section= |
+ | == [http://projecteuler.net/index.php?section=problems&id=162 Problem 162] == |
Hexadecimal numbers |
Hexadecimal numbers |
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</haskell> |
</haskell> |
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− | == [http://projecteuler.net/index.php?section= |
+ | == [http://projecteuler.net/index.php?section=problems&id=163 Problem 163] == |
Cross-hatched triangles |
Cross-hatched triangles |
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</haskell> |
</haskell> |
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− | == [http://projecteuler.net/index.php?section= |
+ | == [http://projecteuler.net/index.php?section=problems&id=164 Problem 164] == |
Numbers for which no three consecutive digits have a sum greater than a given value. |
Numbers for which no three consecutive digits have a sum greater than a given value. |
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</haskell> |
</haskell> |
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− | == [http://projecteuler.net/index.php?section= |
+ | == [http://projecteuler.net/index.php?section=problems&id=165 Problem 165] == |
Intersections |
Intersections |
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</haskell> |
</haskell> |
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− | == [http://projecteuler.net/index.php?section= |
+ | == [http://projecteuler.net/index.php?section=problems&id=166 Problem 166] == |
Criss Cross |
Criss Cross |
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</haskell> |
</haskell> |
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− | == [http://projecteuler.net/index.php?section= |
+ | == [http://projecteuler.net/index.php?section=problems&id=167 Problem 167] == |
Investigating Ulam sequences |
Investigating Ulam sequences |
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</haskell> |
</haskell> |
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− | == [http://projecteuler.net/index.php?section= |
+ | == [http://projecteuler.net/index.php?section=problems&id=168 Problem 168] == |
Number Rotations |
Number Rotations |
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</haskell> |
</haskell> |
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− | == [http://projecteuler.net/index.php?section= |
+ | == [http://projecteuler.net/index.php?section=problems&id=169 Problem 169] == |
Exploring the number of different ways a number can be expressed as a sum of powers of 2. |
Exploring the number of different ways a number can be expressed as a sum of powers of 2. |
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</haskell> |
</haskell> |
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− | == [http://projecteuler.net/index.php?section= |
+ | == [http://projecteuler.net/index.php?section=problems&id=170 Problem 170] == |
Find the largest 0 to 9 pandigital that can be formed by concatenating products. |
Find the largest 0 to 9 pandigital that can be formed by concatenating products. |
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Revision as of 13:55, 22 January 2008
Problem 161
Triominoes
Solution:
problem_161 = undefined
Problem 162
Hexadecimal numbers
Solution:
problem_162 = undefined
Problem 163
Cross-hatched triangles
Solution:
problem_163 = undefined
Problem 164
Numbers for which no three consecutive digits have a sum greater than a given value.
Solution:
addDigit x = [[sum [x !! b !! c | c <- [0..9-a-b]] | b <- [0..9-a]] | a<-[0..9]]
x3 = [[10-a-b | b <- [0..9-a]] | a <- [0..9]]
x20 = iterate addDigit x3 !! 17
problem_164 = sum [x20 !! a !! b | a <- [1..9], b <- [0..9-a]]
Problem 165
Intersections
Solution:
problem_165 = undefined
Problem 166
Criss Cross
Solution:
problem_166 =
sum [ product (map count [[0, c, b-d, a-b-d],
[0, b-a, c+d-a, b+d-a],
[0, -b-c, a-b-c-d, -c-d],
[0, a, d, c+d]])|
a <- [-9..9],
b <- [-9+a..9+a],
c <- [-9..9],
d <- [-9+a-c..9+a-c]]
where
count xs
|u<l=0
|otherwise=u-l+1
where
l = -minimum xs
u = 9-maximum xs
Problem 167
Investigating Ulam sequences
Solution:
problem_167 = undefined
Problem 168
Number Rotations
Solution:
problem_168 = undefined
Problem 169
Exploring the number of different ways a number can be expressed as a sum of powers of 2.
Solution:
problem_169 = undefined
Problem 170
Find the largest 0 to 9 pandigital that can be formed by concatenating products.
Solution:
problem_170 = undefined