some exercises

Author: Juude

excel-sheet-solumn-number.py

@@ -0,0 +1,8 @@
+class Solution:
+    def titleToNumber(self, s):
+        return reduce(lambda x, y: x* 26 + y, map(lambda x : ord(x) - 64, s))
+
+solution = Solution()
+print solution.titleToNumber("A")
+print solution.titleToNumber("AB")
+

factorial-trailing-zeros.py

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+#!/usr/bin/env python
+
+class Solution:
+    def trailingZeros(self, n):
+        sum,pow5 = 0, 5
+        while(n >= pow5):
+            sum += n/pow5
+            pow5 *= 5
+        return sum
+
+solution = Solution()
+print "trailing of is 25", solution.trailingZeros(25)
+print "trailing of is 100", solution.trailingZeros(100)

number-of-1-bits.py

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+#!/usr/bin/env python
+class Solution:
+    def hammingWeight(self, n):
+        weight = 0
+        nn = -n if n < 0 else n
+        while(nn != 0):
+            weight +=  nn % 2
+            nn = nn / 2
+        return weight
+a = Solution()
+print a.hammingWeight(7)
+print a.hammingWeight(-7)
+a.hammingWeight(7)

pascals-triangle.py

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+import sys
+class Solution:
+    def generate(self, numRows):
+        pascal = []
+        for row in range(0, numRows):
+            cur_list = [ 1 if i == 0 or i == row else pascal[row-1][i] + pascal[row-1][i-1] for i in range(0, row +1)]    
+            pascal.append(cur_list)
+        return pascal
+
+solution = Solution()
+numRows = int(sys.argv[1])
+print "numRows : ", numRows 
+print solution.generate(numRows)

reverse-bits.py

@@ -0,0 +1,13 @@
+#!/usr/bin/env python
+
+class Solution:
+    def reverseBits(self, n):
+        i, l = 0, [0 for i in range(0, 32)]
+        while n > 0:
+            l[i] = n %2
+            n = n / 2
+            i += 1
+        return reduce(lambda x, y: x * 2 + y, l) 
+
+solution = Solution()
+print solution.reverseBits(43261596)