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Formatted question description: https://leetcode.ca/all/2140.html

# 2140. Solving Questions With Brainpower (Medium)

You are given a **0-indexed** 2D integer array `questions`

where `questions[i] = [points`

._{i}, brainpower_{i}]

The array describes the questions of an exam, where you have to process the questions **in order** (i.e., starting from question `0`

) and make a decision whether to **solve** or **skip** each question. Solving question `i`

will **earn** you `points`

points but you will be _{i}**unable** to solve each of the next `brainpower`

questions. If you skip question _{i}`i`

, you get to make the decision on the next question.

- For example, given
`questions = [[3, 2], [4, 3], [4, 4], [2, 5]]`

:- If question
`0`

is solved, you will earn`3`

points but you will be unable to solve questions`1`

and`2`

. - If instead, question
`0`

is skipped and question`1`

is solved, you will earn`4`

points but you will be unable to solve questions`2`

and`3`

.

- If question

Return *the maximum points you can earn for the exam*.

**Example 1:**

Input:questions = [[3,2],[4,3],[4,4],[2,5]]Output:5Explanation:The maximum points can be earned by solving questions 0 and 3. - Solve question 0: Earn 3 points, will be unable to solve the next 2 questions - Unable to solve questions 1 and 2 - Solve question 3: Earn 2 points Total points earned: 3 + 2 = 5. There is no other way to earn 5 or more points.

**Example 2:**

Input:questions = [[1,1],[2,2],[3,3],[4,4],[5,5]]Output:7Explanation:The maximum points can be earned by solving questions 1 and 4. - Skip question 0 - Solve question 1: Earn 2 points, will be unable to solve the next 2 questions - Unable to solve questions 2 and 3 - Solve question 4: Earn 5 points Total points earned: 2 + 5 = 7. There is no other way to earn 7 or more points.

**Constraints:**

`1 <= questions.length <= 10`

^{5}`questions[i].length == 2`

`1 <= points`

_{i}, brainpower_{i}<= 10^{5}

**Related Topics**:

Array, Dynamic Programming

**Similar Questions**:

## Solution 1. DP

```
// OJ: https://leetcode.com/problems/solving-questions-with-brainpower/
// Time: O(N)
// Space: O(N)
class Solution {
public:
long long mostPoints(vector<vector<int>>& A) {
long long N = A.size();
vector<long long> dp(N + 2);
for (int i = 0; i < N; ++i) {
int next = i + A[i][1] + 2;
if (next > N) next = N + 1;
dp[i + 1] = max(dp[i + 1], dp[i]);
dp[next] = max(dp[next], dp[i + 1] + A[i][0]);
}
return *max_element(begin(dp), end(dp));
}
};
```