Difference between revisions of "Euler problems/161 to 170"
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| + | Do them on your own! |
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| − | == [http://projecteuler.net/index.php?section=problems&id=161 Problem 161] == |
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| − | Triominoes |
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| − | |||
| − | Solution: |
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| − | <haskell> |
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| − | problem_161 = undefined |
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| − | </haskell> |
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| − | |||
| − | == [http://projecteuler.net/index.php?section=problems&id=162 Problem 162] == |
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| − | Hexadecimal numbers |
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| − | |||
| − | Solution: |
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| − | <haskell> |
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| − | problem_162 = undefined |
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| − | </haskell> |
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| − | |||
| − | == [http://projecteuler.net/index.php?section=problems&id=163 Problem 163] == |
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| − | Cross-hatched triangles |
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| − | |||
| − | Solution: |
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| − | <haskell> |
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| − | problem_163 = undefined |
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| − | </haskell> |
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| − | |||
| − | == [http://projecteuler.net/index.php?section=problems&id=164 Problem 164] == |
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| − | Numbers for which no three consecutive digits have a sum greater than a given value. |
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| − | |||
| − | Solution: |
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| − | <haskell> |
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| − | addDigit x = [[sum [x !! b !! c | c <- [0..9-a-b]] | b <- [0..9-a]] | a<-[0..9]] |
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| − | x3 = [[10-a-b | b <- [0..9-a]] | a <- [0..9]] |
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| − | x20 = iterate addDigit x3 !! 17 |
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| − | problem_164 = sum [x20 !! a !! b | a <- [1..9], b <- [0..9-a]] |
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| − | </haskell> |
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| − | |||
| − | == [http://projecteuler.net/index.php?section=problems&id=165 Problem 165] == |
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| − | Intersections |
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| − | |||
| − | Solution: |
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| − | <haskell> |
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| − | problem_165 = undefined |
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| − | </haskell> |
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| − | |||
| − | == [http://projecteuler.net/index.php?section=problems&id=166 Problem 166] == |
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| − | Criss Cross |
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| − | |||
| − | Solution: |
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| − | <haskell> |
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| − | problem_166 = |
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| − | sum [ product (map count [[0, c, b-d, a-b-d], |
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| − | [0, b-a, c+d-a, b+d-a], |
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| − | [0, -b-c, a-b-c-d, -c-d], |
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| − | [0, a, d, c+d]])| |
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| − | a <- [-9..9], |
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| − | b <- [-9+a..9+a], |
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| − | c <- [-9..9], |
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| − | d <- [-9+a-c..9+a-c]] |
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| − | where |
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| − | count xs |
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| − | |u<l=0 |
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| − | |otherwise=u-l+1 |
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| − | where |
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| − | l = -minimum xs |
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| − | u = 9-maximum xs |
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| − | </haskell> |
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| − | |||
| − | == [http://projecteuler.net/index.php?section=problems&id=167 Problem 167] == |
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| − | Investigating Ulam sequences |
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| − | |||
| − | Solution: |
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| − | <haskell> |
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| − | problem_167 = undefined |
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| − | </haskell> |
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| − | |||
| − | == [http://projecteuler.net/index.php?section=problems&id=168 Problem 168] == |
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| − | Number Rotations |
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| − | |||
| − | Solution: |
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| − | <haskell> |
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| − | problem_168 = undefined |
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| − | </haskell> |
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| − | |||
| − | == [http://projecteuler.net/index.php?section=problems&id=169 Problem 169] == |
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| − | Exploring the number of different ways a number can be expressed as a sum of powers of 2. |
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| − | |||
| − | Solution: |
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| − | <haskell> |
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| − | problem_169 = undefined |
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| − | </haskell> |
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| − | |||
| − | == [http://projecteuler.net/index.php?section=problems&id=170 Problem 170] == |
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| − | Find the largest 0 to 9 pandigital that can be formed by concatenating products. |
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| − | |||
| − | Solution: |
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| − | <haskell> |
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| − | problem_170 = undefined |
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| − | </haskell> |
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Revision as of 21:43, 29 January 2008
Do them on your own!