Difference between revisions of "Euler problems/171 to 180"
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| − | == [http://projecteuler.net/index.php?section=problems&id= |
+ | == [http://projecteuler.net/index.php?section=problems&id=171 Problem 171] == |
| + | Finding numbers for which the sum of the squares of the digits is a square. |
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| − | Triominoes |
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Solution: |
Solution: |
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<haskell> |
<haskell> |
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| − | + | problem_171 = undefined |
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</haskell> |
</haskell> |
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| − | == [http://projecteuler.net/index.php?section=problems&id= |
+ | == [http://projecteuler.net/index.php?section=problems&id=172 Problem 172] == |
| + | Investigating numbers with few repeated digits. |
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| − | Hexadecimal numbers |
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Solution: |
Solution: |
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<haskell> |
<haskell> |
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| − | + | problem_172 = undefined |
|
</haskell> |
</haskell> |
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| − | == [http://projecteuler.net/index.php?section=problems&id= |
+ | == [http://projecteuler.net/index.php?section=problems&id=173 Problem 173] == |
| + | Using up to one million tiles how many different "hollow" square laminae can be formed? |
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| − | Cross-hatched triangles |
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| − | |||
Solution: |
Solution: |
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<haskell> |
<haskell> |
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| + | problem_173= |
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| ⚫ | |||
| + | let c=div (10^6) 4 |
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| + | xm=floor$sqrt $fromIntegral c |
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| ⚫ | |||
| + | in sum k-(div (xm*(xm+1)) 2) |
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</haskell> |
</haskell> |
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| − | == [http://projecteuler.net/index.php?section=problems&id= |
+ | == [http://projecteuler.net/index.php?section=problems&id=174 Problem 174] == |
| + | Counting the number of "hollow" square laminae that can form one, two, three, ... distinct arrangements. |
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| − | Numbers for which no three consecutive digits have a sum greater than a given value. |
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Solution: |
Solution: |
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<haskell> |
<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> |
</haskell> |
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| − | == [http://projecteuler.net/index.php?section=problems&id= |
+ | == [http://projecteuler.net/index.php?section=problems&id=175 Problem 175] == |
| ⚫ | |||
| − | Intersections |
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| − | |||
Solution: |
Solution: |
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<haskell> |
<haskell> |
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| − | + | problem_175 = undefined |
|
</haskell> |
</haskell> |
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| − | == [http://projecteuler.net/index.php?section=problems&id= |
+ | == [http://projecteuler.net/index.php?section=problems&id=176 Problem 176] == |
| + | Rectangular triangles that share a cathetus. |
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| − | Criss Cross |
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| − | |||
Solution: |
Solution: |
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<haskell> |
<haskell> |
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| + | problem_176 = undefined |
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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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| ⚫ | |||
| − | 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> |
</haskell> |
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| − | == [http://projecteuler.net/index.php?section=problems&id= |
+ | == [http://projecteuler.net/index.php?section=problems&id=177 Problem 177] == |
| + | Integer angled Quadrilaterals. |
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| − | Investigating Ulam sequences |
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Solution: |
Solution: |
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<haskell> |
<haskell> |
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| − | + | problem_177 = undefined |
|
</haskell> |
</haskell> |
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| − | == [http://projecteuler.net/index.php?section=problems&id= |
+ | == [http://projecteuler.net/index.php?section=problems&id=178 Problem 178] == |
| + | Step Numbers |
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| − | Number Rotations |
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| − | |||
Solution: |
Solution: |
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<haskell> |
<haskell> |
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| − | + | problem_178 = undefined |
|
</haskell> |
</haskell> |
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| − | == [http://projecteuler.net/index.php?section=problems&id= |
+ | == [http://projecteuler.net/index.php?section=problems&id=179 Problem 179] == |
| + | Consecutive positive divisors. |
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| ⚫ | |||
| − | |||
Solution: |
Solution: |
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<haskell> |
<haskell> |
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| − | + | problem_179 = undefined |
|
</haskell> |
</haskell> |
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| − | == [http://projecteuler.net/index.php?section=problems&id= |
+ | == [http://projecteuler.net/index.php?section=problems&id=180 Problem 180] == |
| − | Find the largest 0 to 9 pandigital that can be formed by concatenating products. |
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Solution: |
Solution: |
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<haskell> |
<haskell> |
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| − | + | problem_180 = undefined |
|
</haskell> |
</haskell> |
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Revision as of 13:27, 28 January 2008
Problem 171
Finding numbers for which the sum of the squares of the digits is a square.
Solution:
problem_171 = undefined
Problem 172
Investigating numbers with few repeated digits.
Solution:
problem_172 = undefined
Problem 173
Using up to one million tiles how many different "hollow" square laminae can be formed? Solution:
problem_173=
let c=div (10^6) 4
xm=floor$sqrt $fromIntegral c
k=[div c x|x<-[1..xm]]
in sum k-(div (xm*(xm+1)) 2)
Problem 174
Counting the number of "hollow" square laminae that can form one, two, three, ... distinct arrangements.
Solution:
problem_174 = undefined
Problem 175
Fractions involving the number of different ways a number can be expressed as a sum of powers of 2. Solution:
problem_175 = undefined
Problem 176
Rectangular triangles that share a cathetus. Solution:
problem_176 = undefined
Problem 177
Integer angled Quadrilaterals.
Solution:
problem_177 = undefined
Problem 178
Step Numbers Solution:
problem_178 = undefined
Problem 179
Consecutive positive divisors. Solution:
problem_179 = undefined
Problem 180
Solution:
problem_180 = undefined