## DEV Community

Abhishek Chaudhary

Posted on

# Boats to Save People

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)

Example 2:

Input: people = [3,2,2,1], limit = 3
Output: 3
Explanation: 3 boats (1, 2), (2) and (3)

Example 3:

Input: people = [3,5,3,4], limit = 5
Output: 4
Explanation: 4 boats (3), (3), (4), (5)

Constraints:

• `1 <= people.length <= 5 * 104`
• `1 <= people[i] <= limit <= 3 * 104`

SOLUTION:

``````class Solution:
def numRescueBoats(self, people: List[int], limit: int) -> int:
people.sort()
n = len(people)
ctr = 0
i, j = 0, n - 1
while i <= j:
ctr += 1
if people[i] + people[j] <= limit:
i += 1
j -= 1
return ctr
``````