[swift] LeetCode 657. Judge Route Circle

Initially, there is a Robot at position (0, 0). Given a sequence of its moves, judge if this robot makes a circle, which means it moves back to the original place.

The move sequence is represented by a string. And each move is represent by a character. The valid robot moves are R (Right), L (Left), U (Up) and D (down). The output should be true or false representing whether the robot makes a circle.

Example 1:

Input: “UD”

Output: true

Example 2:

Input: “LL”

Output: false

return moves.filter({$0 == "U"}).count == moves.filter({$0 == "D"}).count && moves.filter({$0 == "R"}).count == moves.filter({$0 == "L"}).count

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