# Boats to Save People

The `i`-th person has weight `people[i]`, and each boat can carry a maximum weight of `limit`.

Each boat carries at most 2 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.  (It is guaranteed each person can be carried by a boat.)

**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)
```

**Note**:

* `1 <= people.length <= 50000`
* `1 <= people[i] <= limit <= 30000`

```java
class Solution {
    public int numRescueBoats(int[] people, int limit) {
        Arrays.sort(people);
        int i, j;
        for (i = 0, j = people.length - 1; i <= j; --j)
            // If lighest and heaviest wt persons can sit together,
            // then send them together
            // otherwise send heaviest weight alone
            if (people[i] + people[j] <= limit)
                ++i;
        return people.length - 1 - j;
    }
}
```
