# Function to sum values of most significant digit contained

1. For each subsequence, look at its position in the original decimal representation of $$\x\$$. Let's say that the most significant digit it contained was the $$\e\$$-th digit, where $$\e=0\$$ corresponds to the least significant digit of $$\x\$$. For example, $$\388, 822, 442\$$ can be split into subsequences "3", "888", "22", "44", "2", where $$\e=7\$$ for the sequence "888" and $$\e=4\$$ for the sequence "22".

2. The value of a subsequence which contains a digit $$\d\$$ repeated one or more times is $$\d \cdot 10^e\$$.

1. $$\f(x)\$$ is the sum of values of these subsequences. For example, $$\f(388, 822, 442) = 3 \cdot 10^8 + 8 \cdot 10^7 + 2 \cdot 10^4 + 4 > \cdot 10^2 + 2 \cdot 10^0\$$.

2. Since this number could be very large, compute it modulo $$\109+7\$$.

### INPUT

1. The first line of the input contains a single integer denoting the number of cases

2. The first line of each test case contains two space-separated integers

3. The second line contains two space-separated integers $$\N > 10^{18}\$$

from itertools import groupby
def encode(num):
out , num = [] , list(map(int , str(num)))
for v, g in groupby( enumerate(num), lambda k: k[1] ):
l = [*g]
for i in l:
out.append((abs(l[0][0]- len(num) + 1)))
s , value = 0 , False
for i in range(len(num)):
if value == num[i]: pass
else:
s += num[i]*10**out[i]
value = num[i]
return s

for i in range(int(input())):
start = list(map( int , input().split()))
end , output = list(map( int , input().split())) , 0
for num in range(start[1] , end[1]+1):
output += encode(num)
print(output)

• – Martin R Aug 2 at 19:51
• kinda but stuck TLE – code_guest Aug 2 at 19:51
• This challenge is using the term "subsequence" in an unconventional way. I'd call them substrings. – 200_success Aug 2 at 20:18
• @200_success i worked on your "substrings" concept and my time dropped about 12 sec but still TLE – code_guest Aug 5 at 20:27