有些测试用例没有运行，但有些是在概率方面

Question

I have a program in which it rolls five dice and assigns a hand to the rolls. ie nothing, a pair, two pair, three of a kind, full house, four of a kind, five of a kind. The code runs 1000000 times and gives percentage chances for each roll. Below I have attached general percentages my code should output near:

Case 1, None alike, is 0.092533
Case 2, One pair, is 0.462799
Case 3, Two pair, is 0.231789
Case 4, Three of a kind, is 0.154192
Case 5, Full house, is 0.038595
Case 6, Four of a kind, is 0.019316
Case 7, Five of a kind, is 0.000776

However my code gives the following output:

Case 1, None alike is 0.093099
Case 2, One pair is 0.384768
Case 3, Two pair is 0.076921
Case 4, Three of a kind is 0.15485
Case 5, Full House is 0.270349
Case 6, Four of a kind is 0.019281
Case 7, Five of a kind is7.33E-4

I don't understand why my programs percentages are off for one pair, two pairs, and full house. I have gone through and tested my logic but it is sound from what I have seen. Originally, my one pair was correct but my two pair was 0.0. Below is my original logic which causes the two pair to be 0 and my pair to be correct.

I, however, changed it to the current logic to get the current output. I would appreciate another set of eyes to take a look and let me know if they could catch something. Below is my code:

Answer 1

Change 1 :

if (hand < 6) {
                int counter3 = 0;
                int counter2 = 0;
                for (int j = 0; j < length; j++) {
                     if (counts[j] == 3) {
                        counter3++;
                     }
                     if (counts [j] == 2) {
                        counter2++;
                     } 
                }
                if (counter3 == 1 && counter2 == 1) {
                    hand = 5;
                }
            }

Change 2:

if (hand < 4) {
                int newcounter = 0;
                for (int j = 0; j < length; j++) {
                    if (counts[j] == 2) {
                       newcounter++;
                    }
                }
                if (newcounter==2) {
                        hand = 3;
                    }
                if (newcounter == 1) { hand = 2; }
}

Change 3 :

Please remove if( hand < 3) part of code.

Updated my answer. In your code the counter variable (when you're trying to check "full house") was becoming 2 due to two pairs (ex : counts = 020200) not due to full house (ex: counts = 300200). Hence, it wasn't counting the two pairs in the following code where it was supposed to because hand was already becoming 5, so it didn't go inside any other if parts below although it was supposed to go inside if(hand<3) . Hope it will fix the issue.

Answer 2

See comment in code

   if (hand < 4) {
        int newcounter = 0;
        boolean firstp = false;
        boolean secondp = false;
        for (int j = 0; j < length; j++) {
            firstp = false;
            secondp = false;
            if (counts[j] == 2) {
               firstp = true; <---- THIS 
            }
            if (counts[j] == 2) {
               secondp = true; <---- AND THIS will always hit together as j never changes from the first if to second if
          //     break;
            }
        }
            if (firstp && secondp) {
                hand = 3; <---- firstp always equal to secondp, I would be surprised to see hand ever = 2
            }
    }

I modified your code. The original logic is a little bit messy. I made some slight improvement but hopefully better. Not perfect though.

import java.util.*;
public class PokerDice {
    public static void main(String[] args) {
        double none = 0;
        double  pair = 0;
        double twop = 0;
        double  threep = 0;
        double  full = 0;
        double fourp = 0;
        double fivep = 0;

        for (int i = 0; i<=1000000; i++) {
            int [] rolls = new int[5];
            for (int j = 0; j < 5; j++) {
                rolls[j] = (int)(1 + (Math.random()*(6)));
            }
            int[] counts = Counts(rolls);

            boolean has_two = false;
            boolean has_three = false;

            none++;

            for (int j = 0; j < counts.length; j++) {

                if (counts[j] == 4) {
                    fourp++;
                    none--;
                    break;
                }
                if (counts[j] == 5) {
                    fivep++;
                    none--;
                    break;
                }
                if (counts[j] == 3) {
                    has_three = true;

                    if (has_two) {
                        full++;
                        pair--;
                        break;
                    } else {
                        none--;
                        threep++;
                    }
                }
                if (counts[j] == 2) {
                    if (has_two) {
                        twop++;
                        pair--;
                        break;
                    }
                    else if (has_three) {
                        full++;
                        threep--;
                        break;
                    } else {
                        has_two = true;
                        pair++;
                        none--;
                    }
                }
            }
        }
        fivep/=1000000;
        fourp/=1000000;
        full/=1000000;
        threep/=1000000;
        twop/=1000000;
        pair/=1000000;
        none/=1000000;
        System.out.println("Poker Dice Probability Calculator");
        System.out.println("Running 1,000,000 trials");
        System.out.println();
        System.out.println("Case 1, None alike is "+none);
        System.out.println("Case 2, One pair is "+pair);
        System.out.println("Case 3, Two pair is "+twop);
        System.out.println("Case 4, Three of a kind is "+threep);
        System.out.println("Case 5, Full House is "+full);
        System.out.println("Case 6, Four of a kind is "+fourp);
        System.out.println("Case 7, Five of a kind is"+fivep);             
    }
    public static int[] Counts (int [] rolled) {
        int one = 0;
        int two = 0;
        int three = 0;
        int four = 0;
        int five = 0;
        int six = 0;
        int len = rolled.length;
        int [] rolltimes = new int[6];
        for (int i = 0; i<len; i++) {
            if (rolled [i] == 1) {
                one++;
            }
             else if (rolled [i] == 2) {
                two++;
            }
            else if (rolled [i] == 3) {
                three++;
            }
            else if (rolled [i] == 4) {
                four++;
            }
            else if (rolled [i] == 5) {
                five++;
            }
            else if (rolled [i] == 6) {
                six++;
            }
        }
        rolltimes[0] = one;
        rolltimes[1] = two;
        rolltimes[2] = three;
        rolltimes[3] = four;
        rolltimes[4] = five;
        rolltimes[5] = six;
        return rolltimes;
    }


}