added problem 881

Author: SHA65536

problems/problem0881/life_boats.go

@@ -0,0 +1,29 @@
+package problem0881
+
+import "sort"
+
+/*
+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.
+*/
+
+func numRescueBoats(people []int, limit int) int {
+	var light, heavy, res int
+	// Sort from lightest to heaviest
+	sort.Ints(people)
+	// Start from both ends and approach the middle
+	for heavy = len(people) - 1; light <= heavy; res++ {
+		if people[light]+people[heavy] <= limit {
+			// If both the current heaviest an current lightest can
+			// go in the same boat, pair them up
+			light++
+			heavy--
+		} else {
+			// If not, heaviest will go alone
+			heavy--
+		}
+	}
+	return res
+}

problems/problem0881/life_boats_test.go

@@ -0,0 +1,32 @@
+package problem0881
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+type Result struct {
+	Input    []int
+	Limit    int
+	Expected int
+}
+
+var Results = []Result{
+	{[]int{1, 2}, 3, 1},
+	{[]int{3, 2, 2, 1}, 3, 3},
+	{[]int{3, 5, 3, 4}, 5, 4},
+}
+
+func TestLifeBoats(t *testing.T) {
+	assert := assert.New(t)
+
+	for _, res := range Results {
+		want := res.Expected
+		temp := make([]int, len(res.Input))
+		copy(temp, res.Input)
+		got := numRescueBoats(temp, res.Limit)
+		assert.Equal(want, got, fmt.Sprintf("%+v", res))
+	}
+}

readme.md

@@ -275,6 +275,7 @@ Each problem is in it's own directory, with test files. There are helper package
 | 0872 | [Leaf-Similar Trees](https://leetcode.com/problems/leaf-similar-trees) | [My Solution](./problems/problem0872) | ✅ |
 | 0875 | [Koko Eating Bananas](https://leetcode.com/problems/koko-eating-bananas) | [My Solution](./problems/problem0875) | ✅ |
 | 0876 | [Middle of the Linked List](https://leetcode.com/problems/middle-of-the-linked-list) | [My Solution](./problems/problem0876) | ✅ |
+| 0881 | [Boats to Save People](https://leetcode.com/problems/boats-to-save-people) | [My Solution](./problems/problem0881) | ✅ |
 | 0885 | [Spiral Matrix III](https://leetcode.com/problems/spiral-matrix-iii) | [My Solution](./problems/problem0885) | ✅ |
 | 0886 | [Possible Bipartition](https://leetcode.com/problems/possible-bipartition) | [My Solution](./problems/problem0886) | ✅ |
 | 0888 | [Fair Candy Swap](https://leetcode.com/problems/fair-candy-swap) | [My Solution](./problems/problem0888) | ✅ |