Merge branch 'MySolution' into 'master' (d6a16f5d) · Commits · Zane Safi Mroue / hw1p1

src/edu/bu/ec504/hw1p1/MyDistinctCounter.java

+57 −6

Original line number	Diff line number	Diff line
		package edu.bu.ec504.hw1p1;
		import java.nio.charset.StandardCharsets;
		import java.util.BitSet;



		import static java.lang.Math.ceil;

		/**
		* This is a trivial modification!
		*/
		public class MyDistinctCounter extends DistinctCounter {

		/**
		* @inheritDoc
		*/
		public MyDistinctCounter(int memBits) {
		super(memBits);
		}

		/**
		* @inheritDoc
		*/
		@Override
		void saw(String newElement) {
		mem.set(Math.abs(newElement.hashCode()%(mem.len)));
		public void saw(String newElement) {
		int hash = newElement.hashCode();
		hash = Math.abs(hash);
		int pos = Integer.numberOfTrailingZeros(hash);
		//System.out.println(pos);
		if (pos < mem.len) {
		mem.set(pos);
		}
		}


		/**
		* @inheritDoc
		*/
		@Override
		Integer numDistinct() {
		return mem.bits.cardinality();
		public Integer numDistinct() {
		int bitsSet = 0;
		for (int i = 0; i < mem.len; i++) {
		if (mem.get(i)) {
		bitsSet++;
		}
		}
		if (bitsSet == 0) {
		return 0;
		}

		double correctionFactor = calculateCorrectionFactor(bitsSet, mem.len);
		double res;
		int INTres;
		int R = -1;
		for (int i = 0; i < mem.len; i++){
		if (!this.mem.get(i)){
		R = i;
		break;
		}
		}
		if (R == -1){
		res = Math.pow(2, mem.len) * correctionFactor;
		}else{
		res = (Math.pow(2, R) *0.77351);
		}
		res = Math.ceil(res);
		INTres = (int) res;
		return INTres;
		}

		private double calculateCorrectionFactor(int bitsSet, int totalBits) {
		double saturationLevel = (double) bitsSet / totalBits;
		double adjus = 0.5;
		if (saturationLevel > 0.95) {
		adjus = 2.95;
		} else if (saturationLevel > 0.5) {
		adjus = 1.4;
		}
		double logAdjustment = Math.log(totalBits) /Math.log(2);
		return adjus *logAdjustment;
		}

		// NESTED CLASSES
		@@ -34,4 +84,5 @@ public class MyDistinctCounter extends DistinctCounter {
		*/
		public static class NotYetImplemented extends RuntimeException {
		}

		}