Boats to Save People
Difficulty: Medium
Category: DSA
Topics: Array, Two Pointers, Greedy, Sorting
Asked at: Roblox, Paypal
You are given an array `people` where `people[i]` is the weight of the `ith` person, and an **infinite number of boats** where each boat can carry a maximum weight of `limit`. Each boat carries at most two people at the same time, provided the sum of the weight of those people is at most `limit`.
Return _the minimum number of boats to carry every given person_.
**Example 1:**
**Input:** people = [1,2], limit = 3
**Output:** 1
**Explanation:** 1 boat (1, 2)
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**Example 2:**
**Input:** people = [3,2,2,1], limit = 3
**Output:** 3
**Explanation:** 3 boats (1, 2), (2) and (3)
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**Example 3:**
**Input:** people = [3,5,3,4], limit = 5
**Output:** 4
**Explanation:** 4 boats (3), (3), (4), (5)
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**Constraints:**
- `1 <= people.length <= 5 * 104`
- `1 <= people[i] <= limit <= 3 * 104`