Package g2501_2600.s2585_number_of_ways_to_earn_points

Class Solution

java.lang.Object

g2501_2600.s2585_number_of_ways_to_earn_points.Solution

public class Solution
extends Object

2585 - Number of Ways to Earn Points.<p>Hard</p> <p>There is a test that has <code>n</code> types of questions. You are given an integer <code>target</code> and a <strong>0-indexed</strong> 2D integer array <code>types</code> where <code>types[i] = [count_i, marks_i]</code> indicates that there are <code>count_i</code> questions of the <code>i^th</code> type, and each one of them is worth <code>marks_i</code> points.</p> <p>Return <em>the number of ways you can earn <strong>exactly</strong></em> <code>target</code> <em>points in the exam</em>. Since the answer may be too large, return it <strong>modulo</strong> <code>10⁹ + 7</code>.</p> <p><strong>Note</strong> that questions of the same type are indistinguishable.</p> <ul> <li>For example, if there are <code>3</code> questions of the same type, then solving the <code>1^st</code> and <code>2^nd</code> questions is the same as solving the <code>1^st</code> and <code>3^rd</code> questions, or the <code>2^nd</code> and <code>3^rd</code> questions.</li> </ul> <p><strong>Example 1:</strong></p> <p><strong>Input:</strong> target = 6, types = [[6,1],[3,2],[2,3]]</p> <p><strong>Output:</strong> 7</p> <p><strong>Explanation:</strong> You can earn 6 points in one of the seven ways:</p> <ul> <li>Solve 6 questions of the 0^th type: 1 + 1 + 1 + 1 + 1 + 1 = 6</li> <li>Solve 4 questions of the 0^th type and 1 question of the 1^st type: 1 + 1 + 1 + 1 + 2 = 6</li> <li>Solve 2 questions of the 0^th type and 2 questions of the 1^st type: 1 + 1 + 2 + 2 = 6</li> <li>Solve 3 questions of the 0^th type and 1 question of the 2^nd type: 1 + 1 + 1 + 3 = 6</li> <li>Solve 1 question of the 0^th type, 1 question of the 1^st type and 1 question of the 2^nd type: 1 + 2 + 3 = 6</li> <li>Solve 3 questions of the 1^st type: 2 + 2 + 2 = 6 - Solve 2 questions of the 2^nd type: 3 + 3 = 6</li> </ul> <p><strong>Example 2:</strong></p> <p><strong>Input:</strong> target = 5, types = [[50,1],[50,2],[50,5]]</p> <p><strong>Output:</strong> 4</p> <p><strong>Explanation:</strong> You can earn 5 points in one of the four ways:</p> <ul> <li>Solve 5 questions of the 0^th type: 1 + 1 + 1 + 1 + 1 = 5</li> <li>Solve 3 questions of the 0^th type and 1 question of the 1^st type: 1 + 1 + 1 + 2 = 5</li> <li>Solve 1 questions of the 0^th type and 2 questions of the 1^st type: 1 + 2 + 2 = 5</li> <li>Solve 1 question of the 2^nd type: 5</li> </ul> <p><strong>Example 3:</strong></p> <p><strong>Input:</strong> target = 18, types = [[6,1],[3,2],[2,3]]</p> <p><strong>Output:</strong> 1</p> <p><strong>Explanation:</strong> You can only earn 18 points by answering all questions.</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 <= target <= 1000</code></li> <li><code>n == types.length</code></li> <li><code>1 <= n <= 50</code></li> <li><code>types[i].length == 2</code></li> <li><code>1 <= count_i, marks_i <= 50</code></li> </ul>

Constructor Summary

Constructors

Constructor	Description
Solution()

Method Summary

Modifier and Type	Method	Description
int	waysToReachTarget(int target, int[][] types)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

Solution

public Solution()

Method Details

waysToReachTarget

public int waysToReachTarget(int target,
 int[][] types)