添加 problem 881

Algorithms/881. Boats to Save People/881. Boats to Save People.go

@@ -0,0 +1,24 @@
+package leetcode
+
+import (
+	"sort"
+)
+
+func numRescueBoats(people []int, limit int) int {
+	sort.Ints(people)
+	left, right, res := 0, len(people)-1, 0
+	for left <= right {
+		if left == right {
+			res++
+			return res
+		}
+		if people[left]+people[right] <= limit {
+			left++
+			right--
+		} else {
+			right--
+		}
+		res++
+	}
+	return res
+}

Algorithms/881. Boats to Save People/881. Boats to Save People_test.go

@@ -0,0 +1,63 @@
+package leetcode
+
+import (
+	"fmt"
+	"testing"
+)
+
+type question881 struct {
+	para881
+	ans881
+}
+
+// para 是参数
+// one 代表第一个参数
+type para881 struct {
+	s []int
+	k int
+}
+
+// ans 是答案
+// one 代表第一个答案
+type ans881 struct {
+	one int
+}
+
+func Test_Problem881(t *testing.T) {
+
+	qs := []question881{
+
+		question881{
+			para881{[]int{1, 2}, 3},
+			ans881{1},
+		},
+
+		question881{
+			para881{[]int{3, 2, 2, 1}, 3},
+			ans881{3},
+		},
+
+		question881{
+			para881{[]int{3, 5, 3, 4}, 5},
+			ans881{4},
+		},
+
+		question881{
+			para881{[]int{5, 1, 4, 2}, 6},
+			ans881{2},
+		},
+
+		question881{
+			para881{[]int{3, 2, 2, 1}, 3},
+			ans881{3},
+		},
+	}
+
+	fmt.Printf("------------------------Leetcode Problem 881------------------------\n")
+
+	for _, q := range qs {
+		_, p := q.ans881, q.para881
+		fmt.Printf("【input】:%v       【output】:%v\n", p, numRescueBoats(p.s, p.k))
+	}
+	fmt.Printf("\n\n\n")
+}

Algorithms/881. Boats to Save People/README.md

@@ -0,0 +1,50 @@
+# [881. Boats to Save People](https://leetcode.com/problems/boats-to-save-people/)
+
+## 题目
+
+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:
+
+```c
+Input: people = [1,2], limit = 3
+Output: 1
+Explanation: 1 boat (1, 2)
+```
+
+
+Example 2:
+
+```c
+Input: people = [3,2,2,1], limit = 3
+Output: 3
+Explanation: 3 boats (1, 2), (2) and (3)
+```
+
+
+Example 3:
+
+```c
+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
+
+
+## 题目大意
+
+给出人的重量数组，和一个船最大载重量 limit。一个船最多装 2 个人。要求输出装下所有人，最小需要多少艘船。
+
+先对人的重量进行排序，然后用 2 个指针分别指向一前一后，一起计算这两个指针指向的重量之和，如果小于 limit，左指针往右移动，并且右指针往左移动。如果大于等于 limit，右指针往左移动。每次指针移动，需要船的个数都要 ++。
+
+