## Problem: Count Pairs in an Array

Given an array of integers arr[0..n-1], count all pairs (arr[i], arr[j]) in the such that i*arr[i] > j*arr[j], 0 =< i < j j*arr[j] are
(10, 2) (10, 4) (10, 1) (2, 1) (4, 1)
Input:

The first line of input contains T denoting the no. of test cases . Then T test cases follow . The first line of each test case contains an Integer N and the next line contains N space separated values of the array A[ ] .

Output:

For each test case output the required result in a new line.

Constraints:

1<=T<=100
1<=N<=100
1<=A[ ] <=1000

Example:

Input:
2
7
5 0 10 2 4 1 6
4
8 4 2 1
Output:
5
2

```import itertools
def count_pairs(arr):
"""
counting all pairs in arr such that
i*arr[i] > j*arr[j] and j > i
arr: a list of tuple - [(index, value),...]
"""
# get all pairs
all_pairs = list(itertools.combinations(arr, 2))
# check all pairs for the condition
count_pairs = 0
for pair in all_pairs:
i, j, arr_i, arr_j = pair[0][0], pair[1][0], pair[0][1], pair[1][1]
if i*arr_i > j*arr_j and j > i:
count_pairs += 1
return count_pairs

if __name__ == '__main__':
t = input()
for _ in range(t):
n = input()
arr = map(int, raw_input().strip().split())
arr = [(i,arr_i) for (i, arr_i) in enumerate(arr)]
print count_pairs(arr)
```

**'Life is short, why haven't you learned python yet?'

## Problem:

Given a pattern string and a test string, Your task is to implement RegEx substring matching. If the pattern is preceded by a ^, the pattern(excluding the ^) will be matched with the starting position of the text string. Similarly, if it is preceded by a \$, the pattern(excluding the ^) will be matched with the ending position of the text string. If no such markers are present, it will be checked whether pattern is a substring of test.

Example :

^coal
coaltar
Result : 1
tar\$
coaltar
Result : 1
rat
algorate
Result: 1
abcd
efgh
Result :0
Input: The first line of input contains an integer T denoting the no of test cases . Then T test cases follow. Each test case contains two lines. The first line of each test case contains a pattern string. The second line of each test case consists of a text string.

Output: Corresponding to every test case, print 1 or 0 in a new line.

Constrains:
1<=T<=100
1<=length of the string<=1000

Hint: Choosing the right language will probably help.

Implementation: Python 2.7

```#code
def regx_matching(pattern, string):
if pattern.startswith('^'):
return string.startswith(pattern[1:])
elif pattern.endswith('\$'):
return string.endswith(pattern[:-1])
else:
return pattern in string

if __name__ == '__main__':
t = input()
for _ in range(t):
pattern = raw_input().strip()
string = raw_input().strip()
print 1 if regx_matching(pattern, string) else 0
```

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