881. Boats to Save People
Medium
You are given an array people
wherepeople[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 {
/**
* @param Integer[] $people
* @param Integer $limit
* @return Integer
*/
function numRescueBoats($people, $limit) {
$ans = 0;
$i = 0;
$j = count($people) - 1;
sort($people);
while ($i <= $j) {
$remain = $limit - $people[$j];
$j -= 1;
if ($people[$i] <= $remain) {
$i += 1;
}
$ans += 1;
}
return $ans;
}
}
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