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BAEL-875 code refactoring (#2030)

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Hill-Climbing refactor
This commit is contained in:
Parth Karia 2017-06-09 18:27:29 +05:30 committed by maibin
parent 920167f5b7
commit 4552b8088c
1 changed files with 53 additions and 34 deletions
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51
algorithms/src/main/java/com/baeldung/algorithms/hillclimbing/HillClimbing.java
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@ -5,7 +5,6 @@ import java.util.List;
import java.util.Objects; import java.util.Objects;
import java.util.Optional; import java.util.Optional;
import java.util.Stack; import java.util.Stack;
import java.util.stream.Collectors;
public class HillClimbing { public class HillClimbing {
public static void main(String[] args) { public static void main(String[] args) {
@ -79,6 +78,17 @@ public class HillClimbing {
return listOfStacks.stream() return listOfStacks.stream()
.map(stack -> { .map(stack -> {
return applyOperationsOnState(listOfStacks, stack, currentStateHeuristics, goalStateStack);
})
.filter(Objects::nonNull)
.findFirst()
.orElse(null);
}
/**
* This method applies operations on the current state to get a new state
*/
public State applyOperationsOnState(List<Stack<String>> listOfStacks, Stack<String> stack, int currentStateHeuristics, Stack<String> goalStateStack) {
State tempState; State tempState;
List<Stack<String>> tempStackList = new ArrayList<>(listOfStacks); List<Stack<String>> tempStackList = new ArrayList<>(listOfStacks);
String block = stack.pop(); String block = stack.pop();
@ -91,10 +101,6 @@ public class HillClimbing {
if (tempState == null) if (tempState == null)
stack.push(block); stack.push(block);
return tempState; return tempState;
})
.filter(Objects::nonNull)
.findFirst()
.orElse(null);
} }
/** /**
@ -126,13 +132,7 @@ public class HillClimbing {
Optional<State> newState = currentStackList.stream() Optional<State> newState = currentStackList.stream()
.filter(stack -> stack != currentStack) .filter(stack -> stack != currentStack)
.map(stack -> { .map(stack -> {
stack.push(block); return pushElementToStack(stack, block, currentStackList, currentStateHeuristics, goalStateStack);
int newStateHeuristics = getHeuristicsValue(currentStackList, goalStateStack);
if (newStateHeuristics > currentStateHeuristics) {
return new State(currentStackList, newStateHeuristics);
}
stack.pop();
return null;
}) })
.filter(Objects::nonNull) .filter(Objects::nonNull)
.findFirst(); .findFirst();
@ -140,15 +140,37 @@ public class HillClimbing {
return newState.orElse(null); return newState.orElse(null);
} }
/**
* This method pushes a block to the stack and returns new state if its closer to goal
*/
private State pushElementToStack(Stack stack, String block, List<Stack<String>> currentStackList, int currentStateHeuristics, Stack<String> goalStateStack) {
stack.push(block);
int newStateHeuristics = getHeuristicsValue(currentStackList, goalStateStack);
if (newStateHeuristics > currentStateHeuristics) {
return new State(currentStackList, newStateHeuristics);
}
stack.pop();
return null;
}
/** /**
* This method returns heuristics value for given state with respect to goal * This method returns heuristics value for given state with respect to goal
* state * state
*/ */
public int getHeuristicsValue(List<Stack<String>> currentState, Stack<String> goalStateStack) { public int getHeuristicsValue(List<Stack<String>> currentState, Stack<String> goalStateStack) {
Integer heuristicValue; Integer heuristicValue;
heuristicValue = currentState.stream() heuristicValue = currentState.stream()
.mapToInt(stack -> { .mapToInt(stack -> {
return getHeuristicsValueForStack(stack, currentState, goalStateStack);
})
.sum();
return heuristicValue;
}
/**
* This method returns heuristics value for a particular stack
*/
public int getHeuristicsValueForStack(Stack<String> stack, List<Stack<String>> currentState, Stack<String> goalStateStack) {
int stackHeuristics = 0; int stackHeuristics = 0;
boolean isPositioneCorrect = true; boolean isPositioneCorrect = true;
int goalStartIndex = 0; int goalStartIndex = 0;
@ -162,9 +184,6 @@ public class HillClimbing {
goalStartIndex++; goalStartIndex++;
} }
return stackHeuristics; return stackHeuristics;
})
.sum();
return heuristicValue;
} }
} }