In [2]:

    

#1.1


    

In [29]:

    

def isUnique(s):
    
    count=0
    for i in s:
        if s.count(i)>1:
            count+=1
    return (count==0)


    

In [35]:

    

isUnique('hello')


    

    
Out[35]:





False

In [33]:

    

def isUnique(s):
    
    seen=set()
    for i in s:
        if i in seen:
            return False
        else:
            seen.add(i)
    return True


    

In [36]:

    

#1.2


    

In [41]:

    

def reverse(s):
    
    #base
    if len(s)==1:
        return s
    
    return s[-1]+reverse(s[:-1])


    

In [42]:

    

reverse('hello')


    

    
Out[42]:





'olleh'

In [ ]:

    

#1.3


    

In [45]:

    

def rmDublicate(s):
    return "".join(set(s))


    

In [46]:

    

rmDublicate('hello')


    

    
Out[46]:





'eloh'

In [74]:

    

#1.4


    

In [75]:

    

def isAnagram(s1,s2):
    s1=sorted(s1.lower())
    s2=sorted(s2.lower())
    
    if s1==s2:
        return True
    else:
        return False


    

In [76]:

    

isAnagram('bob','obb')


    

    
Out[76]:





True

In [77]:

    

#1.5


    

In [78]:

    

def replace(s):
    return s.replace(' ','%20')


    

In [79]:

    

replace('hello world')


    

    
Out[79]:





'hello%20world'

In [84]:

    

def rotate_matrix(matrix):
    '''rotates a matrix 90 degrees clockwise'''
    n = len(matrix)
    for layer in range(n // 2):
        first, last = layer, n - layer - 1
        for i in range(first, last):
            # save top
            top = matrix[layer][i]

            # left -> top
            matrix[layer][i] = matrix[-i - 1][layer]

            # bottom -> left
            matrix[-i - 1][layer] = matrix[-layer - 1][-i - 1]

            # right -> bottom
            matrix[-layer - 1][-i - 1] = matrix[i][- layer - 1]

            # top -> right
            matrix[i][- layer - 1] = top
    return matrix


    

In [85]:

    

a=[[1, 2, 3, 4, 5],
[6, 7, 8, 9, 10],
[11, 12, 13, 14, 15],
[16, 17, 18, 19, 20],
[21, 22, 23, 24, 25]]


    

In [86]:

    

rotate_matrix(a)


    

    
Out[86]:





[[21, 16, 11, 6, 1],
 [22, 17, 12, 7, 2],
 [23, 18, 13, 8, 3],
 [24, 19, 14, 9, 4],
 [25, 20, 15, 10, 5]]

In [133]:

    

def zero_matrix(mat):
    m=len(mat)
    n=len(mat[0])
    rows=[]
    cols=[]
    
    for i in range(n):
        for j in range(m):
            if mat[i][j]==0:
                rows.append(i)
                cols.append(j)
                
    for row in rows:
        nullify_row(mat,row)
    for col in cols:
        nullify_col(mat,col)
    
    return mat

def nullify_row(mat,row):
    for i in range(len(mat[0])):
        mat[row][i]=0

def nullify_col(mat,col):
    for i in range(len(mat)):
        mat[i][col]=0


    

In [134]:

    

a=[[1, 2, 3, 4, 5],
[6, 7, 8, 9, 10],
[11, 12, 0, 14, 15],
[16, 17, 18, 19, 20],
[21, 22, 23, 24, 25]]


    

In [135]:

    

zero_matrix(a)


    

    
Out[135]:





[[1, 2, 0, 4, 5],
 [6, 7, 0, 9, 10],
 [0, 0, 0, 0, 0],
 [16, 17, 0, 19, 20],
 [21, 22, 0, 24, 25]]

In [129]:

    

nullify([1, 2, 0, 4, 5])


    

    
Out[129]:





[0, 0, 0, 0, 0]

In [155]:

    

#1.8


    

In [156]:

    

def is_sub(string,sub):
    return string.find(sub)!=-1

def isSubstring(s1,s2):
    
    if len(s1)!=len(s2):
        return False
    return is_sub(s1+s1,s2)


    

In [157]:

    

isSubstring('waterbottle','erbottlewat')


    

    
Out[157]:





True

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