A way to split a big problem into repeat parts and reuse saved answers.
Dynamic Programming is pancake math. Make one bowl of batter, not a new egg mess for every pancake.
It saves repeat answers, then uses them again. You meet it in best-choice or best-path tasks, and in many reinforcement learning methods.
Bellman Equation
Dynamic Programming often uses the Bellman Eq to update answers step by step.
Value Iteration
Value Iteration uses Dynamic Programming to update values again and again.
Policy Iteration
Policy Iter. uses Dynamic Programming to rate a plan and improve it.
Q-Learning
Q-Learning borrows the idea, but it can learn without a full world map.