# ---
# title: 1253. Reconstruct a 2-Row Binary Matrix
# id: problem1253
# author: Tian Jun
# date: 2020-10-31
# difficulty: Medium
# categories: Math, Greedy
# link: <https://leetcode.com/problems/reconstruct-a-2-row-binary-matrix/description/>
# hidden: true
# ---
# 
# Given the following details of a matrix with `n` columns and `2` rows :
# 
#   * The matrix is a binary matrix, which means each element in the matrix can be `0` or `1`.
#   * The sum of elements of the 0-th(upper) row is given as `upper`.
#   * The sum of elements of the 1-st(lower) row is given as `lower`.
#   * The sum of elements in the i-th column(0-indexed) is `colsum[i]`, where `colsum` is given as an integer array with length `n`.
# 
# Your task is to reconstruct the matrix with `upper`, `lower` and `colsum`.
# 
# Return it as a 2-D integer array.
# 
# If there are more than one valid solution, any of them will be accepted.
# 
# If no valid solution exists, return an empty 2-D array.
# 
# 
# 
# **Example 1:**
# 
#     
#     
#     Input: upper = 2, lower = 1, colsum = [1,1,1]
#     Output: [[1,1,0],[0,0,1]]
#     Explanation: [[1,0,1],[0,1,0]], and [[0,1,1],[1,0,0]] are also correct answers.
#     
# 
# **Example 2:**
# 
#     
#     
#     Input: upper = 2, lower = 3, colsum = [2,2,1,1]
#     Output: []
#     
# 
# **Example 3:**
# 
#     
#     
#     Input: upper = 5, lower = 5, colsum = [2,1,2,0,1,0,1,2,0,1]
#     Output: [[1,1,1,0,1,0,0,1,0,0],[1,0,1,0,0,0,1,1,0,1]]
#     
# 
# 
# 
# **Constraints:**
# 
#   * `1 <= colsum.length <= 10^5`
#   * `0 <= upper, lower <= colsum.length`
#   * `0 <= colsum[i] <= 2`
# 
# 
## @lc code=start
using LeetCode

## add your code here:
## @lc code=end
