golu-and-coins-1
Problem Description
Golu is given a task of clearing coins fallen down on floor. Naughty being his modus operandi, he thought of playing a game while clearing coins. He arranges the coins like an M X N matrix with random heads (1) and tails (0).
In every move, he chooses a sub-matrix of size L X B [such that max(L,B) >1] and interchanges all heads to tails and vice-versa present in the chosen sub-matrix. Then if he finds a 2X2 sub-matrix exclusively of heads anywhere in the M X N matrix, he removes those coins.
Your task is simple. You have to report the minimum no. of moves taken by him before he clears his first 2X2 sub-matrix.
Input:
Your first line of input consists of two numbers M, N. Each of the next M lines consists of N space-separated integers which are either 0 or 1.
Output:
Output a single line answer giving the minimum no. of steps taken before his first clearance. If it is impossible for him to do so, print "-1" (quotes for clarity).
Constraints :
2 ≤ M,N ≤ 10
Author : Srinivas
Testers : Shubham Parekh , Shreyans
(By IIT Kgp HackerEarth Programming Club)
SAMPLE INPUT 2 4 0 0 1 1 0 0 1 1
SAMPLE OUTPUT 0
Contest Information
- Contest ID: 0
- Problem Index:
- Points: 0.0
- Rating: 0
- Tags: None
- Time Limit: None seconds
- Memory Limit: 0 bytes
Task
Solve this competitive programming problem. Provide a complete solution that handles all the given constraints and edge cases.