【leetcode】判断路径是否相交

bool isPathCrossing(char * path){
    int i=0,x=0,y=0;
    int len = strlen(path);
    int** hhash = (int**)calloc(2*len+1,sizeof(int*));
    for (;i<=len;i++)
    {
        if (!hhash[x+len])
        {
            hhash[x+len] = (int*)calloc(2*len+1,sizeof(int));
            hhash[x+len][y+len]++;
        }
        else
        {
            if (hhash[x+len][y+len]++) return true;
        }
        switch(path[i])
        {
            case 'N': y++; break;
            case 'S': y--; break;
            case 'W': x--; break;
            default: x++; break;
        }
    }
    return false;
}