class Solution:
    """
    @param: strs: a list of strings
    @return: encodes a list of strings to a single string.
    """
    def encode(self, strs):
        arr=[len(strs[0])]
        for x in strs[1:]:
            arr.append(len(x)+arr[-1])
        brr=[str(0)+":"+str(len(strs[0]))]
        for i in range(1,len(arr)):
            brr.append(str(arr[i]-len(strs[i]))+":"+str(arr[i]))
        x="".join(strs)
        y=" ".join(brr)
        a,b=str(0),str(len(x))
        c,d=str(len(x)),str(len(x)+len(y))
        return x+y+"|"+a+","+b+"|"+c+","+d
    """
    @param: str: A string
    @return: dcodes a single string to a list of strings
    """
    def decode(self, strs):
        arr=[]
        for i in range(len(strs)-1,-1,-1):
            if(strs[i]=="|"):
                strs=strs[:i]
                break
            arr.append(strs[i])
        c,d=list(map(int,"".join(arr)[::-1].split(",")))
        arr=[]
        for i in range(len(strs)-1,-1,-1):
            if(strs[i]=="|"):
                strs=strs[:i]
                break
            arr.append(strs[i])
        a,b=list(map(int,"".join(arr)[::-1].split(",")))
        st=strs[a:b]
        y=strs[c:d]
        ans = []
        for x in y.split():
            a,b=list(map(int,x.split(":")))
            ans.append(st[a:b])
        return ans