Added Codechef easy problems

Author: OmkarPathak

CompetitiveProgramming/CodeChef/P37_NDIFFPAL.py

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+# A palindrome is a string that reads same in both directions: forwards and backwards. For example,
+# the strings radar and noon are palindromes, whereas the string chef is not a palindrome as being read
+# backwards is becomes equal to fehc, which is not equal to chef.
+#
+# Let's say that the pair of indices (i, j) denotes a palindrome in some string S iff i ≤ j and the
+# substring starting at the i-th character and ending at the j-th character of S is a palindrome.
+#
+# Given an integer N. Your task is to construct a string S such that there are exactly N different
+# pairs (i, j) that denotes a palindrome.
+#
+# Input
+# The first line of the input contains an integer T denoting the number of test cases. The description
+# of T test cases follows.
+#
+# The first line of each test case contains a single integer N denoting the sought number of pairs that
+# denote palindrome.
+#
+# Output
+# For each test case, output a single line containing a string S, consisting of lowecase Latin letters,
+# and having exactly N distinct palindrome-denoting pairs. If there's a few such strings, output any one.
+#
+# If such string S doesn't exist, output -1 instead of it.
+#
+# Constraints
+# 1 ≤ T ≤ 100
+# 1 ≤ N ≤ 104
+#
+# Example
+# Input:
+# 3
+# 6
+# 7
+# 2
+#
+# Output:
+# noon
+# radar
+# ab
+#
+# Explanation:
+# Example case 1. In the string "noon", the pairs that denote a palindrome are (1-indexed): (1, 1), (1, 4), (2, 2), (2, 3), (3, 3), (4, 4).
+#
+# Example case 2. In the string "radar", the pairs that denote a palindrome are (1-indexed): (1, 1), (1, 5), (2, 2), (2, 4), (3, 3), (4, 4), (5, 5).
+#
+# Example case 3. In the string "ab", the pairs denoting a palindrome are : (1, 1), (2, 2)
+
+for _ in range(int(input())):
+    n = int(input())
+    s = 'abcdefghijklmnopqrstuvwxyz'
+    if (n <= 26):
+        print(s[:n])
+    else:
+        a = n // 26
+        b = n % 26
+        c = a * s
+        c = c + s[:b]
+        print (c)

CompetitiveProgramming/CodeChef/P38_PRINCESS.py

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+# We all know that the princess is very beautiful but one day jealous from her beauty, a person asked a 
+# question from princess in order to check her wisdom. Since princess is not good at programming you need
+# to help her in solving the problem.
+# You are given a string of length N. You have to check among all the the substrings that whether a substring
+# exist or not which is palindrome and having length greater than 1. If such a substring exists then print
+# YES else print NO.
+#
+# Input
+# The first line contains a single integer T, the number of test cases. Each test case is described by a
+# single line containing a string.
+#
+# Output
+# For each test case, output a single line containing the YES or NO.
+#
+# Constraints
+# 1 ≤ T ≤ 10
+# 1 ≤ N ≤ 100000
+#
+# Example
+# Input:
+# 2
+# ab
+# babba
+#
+# Output:
+# NO
+# YES
+# Explanation
+# Example case 1.The only substring whose length is greater than 1 is ab, and its not a palindrome.
+#
+# Example case 2.abba is a substring of the string and its a palindrome thus YES.
+
+def manacher(string):
+
+    string_with_bounds = '#'.join('^{}$'.format(string))
+    length = len(string_with_bounds)
+    P = [0] * length
+    center = right = 0
+
+    for i in range(1, length - 1):
+        P[i] = (right > i) and min(right - i, P[2 * center - i])
+
+        # Attempt to expand palindrome centered at i
+        while string_with_bounds[i + 1 + P[i]] == string_with_bounds[i - 1 - P[i]]:
+            P[i] += 1
+
+        # If palindrome centered at i expand past R,
+        # adjust center based on expanded palindrome.
+        if i + P[i] > right:
+            center, right = i, i + P[i]
+
+    # Find the maximum element in P and return the string
+    maxLen, centerIndex = max((n, i) for i, n in enumerate(P))
+    return string[(centerIndex  - maxLen)//2: (centerIndex  + maxLen)//2]
+
+for _ in range(int(input())):
+    string = input()
+    result = manacher(string)
+    if len(result) > 1:
+    	print('YES')
+    else:
+    	print('NO')

CompetitiveProgramming/CodeChef/P39_ALATE.py

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+# Anmol always comes to class when the class is about to end. Frustrated by this behaviour of Anmol, his
+# teacher has given him a special question as his homework. We all know that Anmol is very weak at computer
+# science thus he came to you for help. Help Anmol in order to solve the problem.
+# You are given an array A of length N(1 indexed). You have to process Q queries of two different types:
+# 1 x — print func(x)
+# 2 x y— change the value of A[x] to y.
+# func(x) is defined as ::
+#
+# func(x)
+# {
+# 	sum = 0 ;
+# 	for(i=x;i<=N;i+=x)
+# 		sum = (sum + A[i]*A[i]) ;
+# 	return sum ;
+# }
+#
+# For each query of type 1 print the value of func(x) in a new line.
+# Input
+# The first line contains a single integer T, the number of test cases.
+# Each test case is described as follows :
+# The first line contains two numbers N and Q.
+# In the next line N space separated numbers denoting the values of the array A.
+# Each of the following Q lines contains a query of one of the above mentioned two types.
+# Note :: Since the test files are large use scanf/printf for I/O.
+#
+# Output
+# For each test case, For each query of type 1 print the required answer.
+#
+#
+# Since the answer can be very large, output it modulo 1000000007
+# Constraints
+# 1 ≤ T ≤ 10
+# 1 ≤ N ≤ 100000
+# 1 ≤ Q ≤ 100000
+# 1 ≤ A[i] ≤ 1e9
+# 1 ≤ x ≤ N
+# 1 ≤ y ≤ 1e9
+#
+# Subtasks
+#
+# Subtask #1 (20 points), Time limit : 1 sec
+# 1 ≤ T<=10, N<=100
+#
+#
+# Subtask #2 (80 points), Time limit : 1 sec
+# 1 ≤ T<=10, N<=100000
+#
+#
+# Example
+# Input:
+# 1
+# 5 3
+# 1 2 3 4 5
+# 1 1
+# 2 2 1
+# 1 2
+# Output:
+# 55
+# 17
+
+def func(x):
+    sum = 0
+    for i in range(x, int(n) + 1, x):
+        sum = sum + array[i] * array[i]
+    return sum
+
+for _ in range(int(input())):
+    n, q = input().split()
+    array = [int(i) for i in input().split()]
+    array.insert(0, 0)
+    for _ in range(int(q)):
+        inputs = [int(i) for i in input().split()]
+        if len(inputs) == 2:
+            print(func(inputs[1]))
+        else:
+            array[inputs[1]] = inputs[2]