【leetcode】657. Judge Route Circle

水深无声 2022-06-10 08:51 146阅读 0赞

**一、题目描述**

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

**思路**：设置初始点的坐标为x=0,y=0，从坐标系的角度来看，Up就是y+1，DOWN就是y-1，Left就是x-1，Right就是x+1，因此按照字符串中的指示走，最后判断x和y的值是否等于（0,0）即可。

**AC代码（c++版）**：

class Solution {
    public:
        bool judgeCircle(string moves) {
            int x=0, y=0;
            int len = moves.size();
            if(len <= 1){
                return false;
            }
            int i;
            for(i=0;i<len;++i){
                switch(moves[i]){
                case 'U': y++; break;
                case 'D': y--; break;
                case 'L': x--; break;
                case 'R': x++; break;
                }
            }//for
            if(x==0 && y==0){
                return true;
            }
            return false;
            
        }
    };

**go语言版代码**

func judgeCircle(moves string) bool {
        n := len(moves)
        count1 := 0
        count2 := 0
        for i:=0;i<n;i++{
                switch moves[i]{
                case 'L':
                        count1++
                case 'R':
                        count1--
                case 'U':
                        count2++
                case 'D':
                        count2--
                }
        }
        if count1==0 && count2==0{
                return true
        }else{
                return false
        }
    }