105 lines
3.1 KiB
Markdown
105 lines
3.1 KiB
Markdown
[< Back](../README.md)
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# Exercise: PacMan AI
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Let's implement a naive AI for PacMan.
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## Background: PacMan Moves
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At each intersection, check if there is a ghost directly inline with that path. If the path is free of ghosts, you are
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allowed to turn there. And if PacMan is moving in a direction, and a ghost enters his path, then PacMan will reverse.
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For example if PacMan is at an intersection and can go either right or up, and there is a ghost in the path going right,
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then PacMan will go up. Then while PacMan is going up, a ghost enters that path, PacMan will go back.
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You only need to worry about the grid itself and any ghosts on the North/South/East/West axis of PacMan.
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## Exercise
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### Part 1
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Implement [PacManAI::pelletClosestToPacman](../../../lib/PacManAI.cpp) and test your implementation with the test
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in [testPacmanAI.cpp](../../../test/testPacmanAI.cpp) called _"Find pellet closest to PacMan"_
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The function should return the position of the pellet that is "closest" to PacMan. One implementation could be to sort
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the vector of pellets by the distance they have to PacMan, and then return the first one.
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```cpp
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GridPosition PacManAI::pelletClosestToPacman(GridPosition pacmanGridPosition,
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std::vector<GridPosition> & pellets) {
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return {0, 0};
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}
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```
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<details>
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<summary>Hint 1</summary>
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Use the `positionDistance` function to find the distance to PacMan.
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</details>
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<details>
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<summary>Hint 2</summary>
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Use the [std::sort](https://en.cppreference.com/w/cpp/algorithm/sort) function to sort the vector.
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</details>
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</details>
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<details>
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<summary>Hint 3</summary>
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[std::sort](https://en.cppreference.com/w/cpp/algorithm/sort) third parameter should be a lambda taking 2 `GridPosition` as parameter,
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and return true if the first parameter is closer from PacMan than the second.
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</details>
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### Part 2
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Implement [PacManAI::isValidMove](../../../lib/PacManAI.cpp) and test your implementation with the test
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in [testPacmanAI.cpp](../../../test/testPacmanAI.cpp) called _"Is valid move"_
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To run the tests through CMake change the last line in [test/CMakeLists.txt](../../../test/CMakeLists.txt) to:
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```
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add_test(NAME pacman_tests COMMAND pacman_tests)
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```
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```cpp
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bool PacManAI::isValidMove(const Move & move) {
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return false;
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}
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```
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<details>
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<summary>Hint 1</summary>
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Use [isWalkableForPacMan](../../../lib/Board.cpp) to make sure PacMan is not walking in ways that are not legal
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</details>
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<details>
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<summary>Hint 2</summary>
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Use [oppositeDirection](../../../lib/include/Direction.hpp) to make sure PacMan doesn't get stuck toggeling back and forth
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</details>
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### Part 3
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Implement [PacManAI::optimalDirection](../../../lib/PacManAI.cpp) and test your implementation with the test
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in [testPacmanAI.cpp](../../../test/testPacmanAI.cpp) called _"Is optimal direction"_
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```cpp
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Direction PacManAI::optimalDirection(const std::array<Move, 4> & moves) {
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return Direction::NONE;
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}
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```
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<details>
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<summary>Hint</summary>
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You can use [std::min_element](https://en.cppreference.com/w/cpp/algorithm/min_element) to find the closest pellet
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</details>
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