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LeetCode刷题：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”

Example 2:

Input: “LL”

算法设计

package com.bean.basic;public class JudgeRouteCircle {    public static boolean judgeCircle(String moves) {        //设定两个变量x，y；分别表示平面图形的横坐标和纵坐标        int x = 0;        int y = 0;        //将字符串转化为字符数组后，进行迭代        for (char ch : moves.toCharArray()) {            /*             * 向上移动的方向，纵坐标 y--             * 向下移动的方向，纵坐标 y++             * 向左移动的方向，横坐标 x--             * 向右移动的方向，横坐标 x++             */            if (ch == 'U') y++;            else if (ch == 'D') y--;            else if (ch == 'R') x++;            else if (ch == 'L') x--;        }        // 路径形成一个环路的条件是：x==0 && y==0        return x == 0 && y == 0;    }    public static void main(String[] args) {        // TODO Auto-generated method stub        //String str="UD";        String str="LL";        if(judgeCircle(str)) {            System.out.println("True");        }else {            System.out.println("False");        }    }}

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