Balance Dresses Across Adjacent Washing Machines

### Problem Machines stand in a line with initial dress counts machines. In one move, any chosen machines may each send one dress to one adjacent machine simultaneously; each sender sends at most one dress in that move. Return the fewest moves needed for all counts to agree, or -1 if balancing is impossible. ```cpp class Solution { public: int findMinMoves(vector<int>& machines); }; ``` ### Examples **Example 1:** ```text machines = [4,0,2] Output: 2 Explanation: [4,0,2] -> [3,1,2] -> [2,2,2]. ``` **Example 2:** ```text machines = [0,4,0] Output: -1 Explanation: Four dresses cannot be split equally among three machines. ``` ### Constraints - There are n=machines.length machines, with n in 1..10000. Every initial count is in 0..100000. ### Clarifying Questions Account for simultaneous transfers, one outgoing dress per chosen machine, cut imbalances and impossible totals. ```hint Read the boundary condition How many dresses must cross the boundary after each prefix of machines? ``` ### Contract considerations Account for simultaneous transfers, one outgoing dress per chosen machine, cut imbalances and impossible totals.