在矩阵中查找非0的唯一元素

def find_unique_nonzero(matrix):
    for i in range(len(matrix)):
        for j in range(len(matrix[i])):
            if matrix[i][j] != 0:
                unique = True
                for k in range(len(matrix)):
                    for l in range(len(matrix[k])):
                        if (k != i or l != j) and matrix[k][l] == matrix[i][j]:
                            unique = False
                            break
                    if not unique:
                        break
                if unique:
                    return matrix[i][j]
    return "未找到唯一的非0元素"

# 示例矩阵
matrix = [
    [0, 0, 0, 0],
    [0, 1, 0, 0],
    [0, 0, 2, 0],
    [0, 0, 0, 3]
]

result = find_unique_nonzero(matrix)
print(result)