【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

这个题就很简单了，说了一圈就是判断有没有回到原点。

/**
 * @param {string} moves
 * @return {boolean}
 */
var judgeCircle = function(moves) {
    if(moves.length%2==1){return fasle;}
    var L=0,R=0,U=0,D=0;
    for(var i =0 ;i<moves.length;i++){
        switch (moves[i])
        {   case "L":
                L++;
                break;
            case "R":
                R++;
                break;
            case "U":
                U++;
                break;
            case "D":
                D++;
                break;
        }
    }
    if(L==R&&U==D){
        return true;
    }else{
        return false;
    }
};

我的思路是先判断是不是一个能被2整除的长度，如果不是，肯定是不能回到原点的。然后初始化了四个变量来记录各个方向走的值，如果左边等于右边并且上等于下，那就是回到原点了，返回true 否则就返回fasle