p178

Author: ashwanikumar04

AllQuestions.md

@@ -2827,7 +2827,7 @@ For example, given the linked list 7 -> 7 -> 3 -> 5 and k = 2, it should become
 Given the linked list 1 -> 2 -> 3 -> 4 -> 5 and k = 3, it should become 3 -> 4
 -> 5 -> 1 -> 2.
 
-## Problem-178:waxing_crescent_moon:
+## [Problem-178](src/main/java/in/ashwanik/dcp/problems/p151_180/p178):sunny:
 
 
 > This problem was asked by Two Sigma.

README.md

@@ -88,6 +88,12 @@ Solutions to the coding problems from [Daily coding problem](https://dailycoding
 |[P28](src/main/java/in/ashwanik/dcp/problems/p1_30/p28)|[P95](src/main/java/in/ashwanik/dcp/problems/p91_120/p95)|
 
 
+## **Two Sigma (2)**
+| | |
+|--|--|
+|[P45](src/main/java/in/ashwanik/dcp/problems/p31_60/p45)|[P178](src/main/java/in/ashwanik/dcp/problems/p151_180/p178)|
+
+
 ## **Square (2)**
 | | |
 |--|--|
@@ -112,12 +118,6 @@ Solutions to the coding problems from [Daily coding problem](https://dailycoding
 |[P34](src/main/java/in/ashwanik/dcp/problems/p31_60/p34)|
 
 
-## **Two Sigma (1)**
-| |
-|--|
-|[P45](src/main/java/in/ashwanik/dcp/problems/p31_60/p45)|
-
-
 ## **Yelp (1)**
 | |
 |--|

src/main/java/in/ashwanik/dcp/problems/p151_180/p178/Readme.md

@@ -0,0 +1,11 @@
+Alice wants to join her school's Probability Student Club. Membership dues are
+computed via one of two simple probabilistic games.
+
+The first game: roll a die repeatedly. Stop rolling once you get a five followed
+by a six. Your number of rolls is the amount you pay, in dollars.
+
+The second game: same, except that the stopping condition is a five followed by
+a five.
+
+Which of the two games should Alice elect to play? Does it even matter? Write a
+program to simulate the two games and calculate their expected value.

src/main/java/in/ashwanik/dcp/problems/p151_180/p178/Solution.java

@@ -0,0 +1,28 @@
+package in.ashwanik.dcp.problems.p151_180.p178;
+
+import java.util.Random;
+
+class Solution {
+    private Random random;
+
+    Solution() {
+        random = new Random();
+    }
+
+    private int dice() {
+        return random.nextInt(6) + 1;
+    }
+
+    int numberOfDiceToWin(int a, int b) {
+        int diceThrown = 1;
+        int current = dice();
+        while (true) {
+            int next = dice();
+            diceThrown++;
+            if (current == a && next == b) {
+                return diceThrown;
+            }
+            current = next;
+        }
+    }
+}

src/test/java/in/ashwanik/dcp/problems/p151_180/p178/SolutionTest.java

@@ -0,0 +1,22 @@
+package in.ashwanik.dcp.problems.p151_180.p178;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+public class SolutionTest {
+    private Solution solution = new Solution();
+
+    @Test
+    void testDice() {
+        assertTrue(count(5, 6) < count(5, 5));
+    }
+
+    private int count(int a, int b) {
+        int count = 0;
+        for (int index = 0; index < 10000; index++) {
+            count = solution.numberOfDiceToWin(a, b);
+        }
+        return count;
+    }
+}