longest sequence of consecutive heads or tails in coinFlip

Question

This program is supposed to simulate 200 coin flips and print out the length of the longest sequence of heads or tails.

Hey guys, I'm new at programming. I'm stuck in the middle of writing this. Can someone help me to understand the logic behind it? Any help would be appreciated.

public class CoinFlips{

  public static void main(String[] args){

    int headsCount=0;
    int tailsCount=0;
    int countTales=0;
    int countHeads=0;

    for (int i=0 ; i<=200; i++){

      double x= Math.random();
      if (x<0.5){
        countTales++;
      }
      else {
        countHeads++;
      }

        //I'm clueless! 
    }

  }

}

Do you know how to find the minimum, or maximum in a sequence? It's the same concept.. — Mike Dinescu, May 16 '14 at 02:40

score 0 · Answer 1 · answered May 16 '14 at 02:53

Use headsCount and tailsCount to track your max values and reset the counters when the sequence switches from heads to tails like this:

if (x < 0.5) {
   countTales++;
   countHeads = 0; // Reset sequence counter for heads
} else {
   countHeads++;
   countTales = 0; // Reset sequence counter for tails
}

if (countTales > tailsCount) {
   tailsCount = countTales;
}
if (countHeads > headsCount) {
   headsCount = countHeads;
}

score -1 · Answer 2 · answered May 16 '14 at 03:04

Try this:

public class CoinFlips{

  public static void main(String[] args){

    private int headsCount, tailsCount, countTails, countHeads, maxHeads, maxTails, lastFlip = 0;
    private static final int HEADS = 1;
    private static final int TAILS = 2;

    for (int i=0 ; i<=200; i++){

      double x= Math.random();
      if (x<0.5){
        if (lastFlip == TAILS) {
           tailsCount++;
           if (tailsCount > maxTails) {
              maxTails = tailsCount;
           }
        } else {
          tailsCount = 1;
        }
        lastFlip = TAILS;
        countTails++;
      }
      else {
        if (lastFlip == HEADS) {
           headsCount++;
           if (headsCount > maxHeads) {
              maxHeads = headsCount;
           }
        } else {
          headsCount = 1;
        }
        countHeads++;
      }


    }

    StringBuilder sb = new StringBuilder();
    sb.append("There were ").append(countHeads)
       .append(" heads flipped with the maximum sequential flips of ")
       .append(maxHeads).append(".\n")
       .append("There were ").append(countTails)
       .append(" tails flipped with the maximum sequential flips of ")
       .append(maxTails).append(".\n");
     System.out.print(sb.toString());
  }

}

`

longest sequence of consecutive heads or tails in coinFlip

2 Answers2