Explain the difference between deadlock states and process lifecycle states, when they can occur, and how they differ from each other.

Mutual blocking (deadlock) and the lifecycle of processes are different concepts, although both are related to process and thread management.

Deadlock:

• A state where two or more processes (or threads) wait forever for each other, each holding a resource needed by the other.
• Occurs when processes acquire resources in the wrong order and cannot continue working.
• Example: process A holds resource 1 and waits for resource 2, while process B holds resource 2 and waits for resource 1.
• In iOS, this can happen due to improper use of locks, for example, when working with GCD or NSLock.

Process lifecycle:

• Describes the stages of a process or thread's existence: creation, execution, waiting, termination.
• In iOS, the application lifecycle includes states: inactive, active, background, suspended, etc.
• The lifecycle manages transitions between states but is not necessarily related to locks.

Differences:

• Deadlock is a synchronization error that leads to process halt.
• The lifecycle is a normal process of managing application or process states.

Thus, deadlock is an issue that arises during the lifecycle, but the lifecycle is a broader concept that describes all stages of a process's existence.