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

bool judgeCircle(char* moves) {

    int i;
    int m=0,n=0;
    for(i=0;moves[i]!='\0';i++){
        switch(moves[i]){
        case 'L':   //向左
            n--;
            break;
        case 'R':  //向右
            n++;
            break;
        case 'U':
            m--;
            break;
        case 'D':
            m++;
            break;
        }
    }
    if(m==0 && n==0) return true;
    else return false;
}