Problem B
Habeas Corpus
“The power to arrest–to deprive a citizen of liberty–must be used fairly, responsibly, and without bias.” –Loretta Lynch.
Due to desperation caused by the global financial crisis, you, left with no other options, decided to rob a bank to survive. Unfortunately, while you were able to escape with a small fortune, the city’s police is now out in full force trying to hunt you down.
The city can be represented as a grid with $R$ rows and $C$ columns. Each block in the city is represented as a cell in this grid. The city has very strict border controls and has shut down all its borders for $24$ hours after the bank robbery to find and arrest you.
You have intercepted the officer’s calls and have discovered that the police force intends to, for the next $24$ hours, search all blocks within $K$ blocks of their current location (that is, all blocks that can be reached by traveling a total of at most $K$ blocks horizontally or vertically). Unfortunately, you don’t know their current location, so you can only assume that they are at some random block, each block with equal probability.
You hence also intend to hide at a random location in the city. You will choose a block uniformly at random and hide there, hoping that it is not a block the police will search. Since you have no idea where the police are, this may unfortunately also be a block the police is currently at (and will definitely search).
You can assume that, unfortunately, the police are very thorough in their search and they will definitely catch you if they search the block you are in. However, if the $24$ hours elapse without the block you are in being searched, you will surely be able to escape as the borders are reopened.
What is the probability that you will evade capture?
Input
The first and only line of input contains three integers, $R$, $C$ ($1 \leq R, C \leq 10^{11}$) and $K$ ($1 \leq K \leq 2\cdot 10^{11}$), the number of rows in the city, the number of columns in the city and the number of blocks the police will search, respectively.
Output
It can be shown that the probability of evading capture can be uniquely represented as an irreducible fraction $p/q$.
Output a single integer on a line by itself, containing the remainder after dividing $p\cdot q^{-1}$ by $10^{11}+3$, where $q^{-1}$ denotes the modular multiplicative inverse of $q$ with respect to the modulus $10^{11}+3$.
The input will be such that $q^{-1}$ always exists.
Sample Input 1 | Sample Output 1 |
---|---|
5 4 2 |
14500000001 |
Sample Input 2 | Sample Output 2 |
---|---|
5 4 100 |
0 |