Description
You are given an array of distinct integers arr and an array of integer arrays pieces, where the integers in pieces are distinct. Your goal is to form arr by concatenating the arrays in pieces in any order. However, you are not allowed to reorder the integers in each array pieces[i].
Return true if it is possible to form the array arr from pieces. Otherwise, return false.
Example 1:
Input: arr = [85], pieces = [[85]]
Output: true
Example 2:
Input: arr = [15,88], pieces = [[88],[15]]
Output: true
Explanation: Concatenate [15] then [88]
Example 3:
Input: arr = [49,18,16], pieces = [[16,18,49]]
Output: false
Explanation: Even though the numbers match, we cannot reorder pieces[0].
Example 4:
Input: arr = [91,4,64,78], pieces = [[78],[4,64],[91]]
Output: true
Explanation: Concatenate [91] then [4,64] then [78]
Example 5:
Input: arr = [1,3,5,7], pieces = [[2,4,6,8]]
Output: false
Constraints:
- 1 <= pieces.length <= arr.length <= 100
sum(pieces[i].length) == arr.length - 1 <= pieces[i].length <= arr.length
- 1 <= arr[i], pieces[i][j] <= 100
- The integers in arr are distinct.
- The integers in pieces are distinct (i.e., If we flatten pieces in a 1D array, all the integers in this array are distinct).
analysis
The meaning of the question is: given arr and pieces, check that pieces can be composed of arr, but the order of pieces[i] cannot be changed. Ideas I refer to the ideas of others. First, if the number contained in pieces is not in arr, it returns False. Then sort the pieces according to the position of arr, and then re-splice them into res. If it is the same as arr, it indicates that it meets the requirements, otherwise the pieces cannot be split by arr.
Code
class Solution:
def canFormArray(self, arr: List[int], pieces: List[List[int]]) -> bool:
for piece in pieces:
if(piece[0] not in arr):
return False
pieces.sort(key=lambda x:arr.index(x[0]))
res=[]
for piece in pieces:
res+=piece
if(res==arr):
return True
else:
return False