import choco.kernel.solver.search.integer.AbstractIntVarSelector;
import choco.kernel.solver.variables.integer.IntDomainVar;
import choco.kernel.solver.variables.AbstractVar;
import choco.kernel.memory.IStateInt;

public class MaxDegreeHeuristic extends AbstractIntVarSelector {

    private IntDomainVar[] vars;                // 0/1 decision variables
    private int n;                              // number of decision variables
    private IStateInt[] deg;                    // number of vertices adjacent to v[i] in candidate set, reversible
    private ReversibleSortedArray candidateSet; // the uninstantiated variables
    private MonitorObject monitor;

    public MaxDegreeHeuristic(IntDomainVar[] vars,IStateInt[] deg,ReversibleSortedArray candidateSet){
	this.vars = vars; n = vars.length; this.deg = deg; this.candidateSet = candidateSet;
	monitor = null;
    }

    public MaxDegreeHeuristic(IntDomainVar[] vars,IStateInt[] deg,ReversibleSortedArray candidateSet,MonitorObject monitor){
	this.vars = vars; n = vars.length; this.deg = deg; this.candidateSet = candidateSet;
	this.monitor = monitor;
    }

    public IntDomainVar selectIntVar(){
	if (monitor != null) monitor.monitor();
	if (candidateSet.isEmpty()) return null;
	else return vars[candidateSet.getFirst()];
    }
}