添加 problem 976

Algorithms/976. Largest Perimeter Triangle/976. Largest Perimeter Triangle.go

@@ -0,0 +1,15 @@
+package leetcode
+
+func largestPerimeter(A []int) int {
+	if len(A) < 3 {
+		return 0
+	}
+	quickSort__(A, 0, len(A)-1)
+
+	for i := len(A) - 1; i >= 2; i-- {
+		if (A[i]+A[i-1] > A[i-2]) && (A[i]+A[i-2] > A[i-1]) && (A[i-2]+A[i-1] > A[i]) {
+			return A[i] + A[i-1] + A[i-2]
+		}
+	}
+	return 0
+}

Algorithms/976. Largest Perimeter Triangle/976. Largest Perimeter Triangle_test.go

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+package leetcode
+
+import (
+	"fmt"
+	"testing"
+)
+
+type question976 struct {
+	para976
+	ans976
+}
+
+// para 是参数
+// one 代表第一个参数
+type para976 struct {
+	one []int
+}
+
+// ans 是答案
+// one 代表第一个答案
+type ans976 struct {
+	one int
+}
+
+func Test_Problem976(t *testing.T) {
+
+	qs := []question976{
+
+		question976{
+			para976{[]int{1, 2}},
+			ans976{0},
+		},
+		question976{
+			para976{[]int{1, 2, 3}},
+			ans976{0},
+		},
+
+		question976{
+			para976{[]int{}},
+			ans976{0},
+		},
+
+		question976{
+			para976{[]int{2, 1, 2}},
+			ans976{5},
+		},
+
+		question976{
+			para976{[]int{1, 1, 2}},
+			ans976{0},
+		},
+
+		question976{
+			para976{[]int{3, 2, 3, 4}},
+			ans976{10},
+		},
+
+		question976{
+			para976{[]int{3, 6, 2, 3}},
+			ans976{8},
+		},
+	}
+
+	fmt.Printf("------------------------Leetcode Problem 976------------------------\n")
+
+	for _, q := range qs {
+		_, p := q.ans976, q.para976
+		fmt.Printf("【input】:%v       【output】:%v\n", p, largestPerimeter(p.one))
+	}
+	fmt.Printf("\n\n\n")
+}

Algorithms/976. Largest Perimeter Triangle/README.md

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+# [976. Largest Perimeter Triangle](https://leetcode.com/problems/largest-perimeter-triangle/)
+
+## 题目
+
+Given an array A of positive lengths, return the largest perimeter of a triangle with non-zero area, formed from 3 of these lengths.
+
+If it is impossible to form any triangle of non-zero area, return 0.
+
+
+Example 1:
+
+```c
+Input: [2,1,2]
+Output: 5
+```
+
+Example 2:
+
+```c
+Input: [1,2,1]
+Output: 0
+```
+
+Example 3:
+
+```c
+Input: [3,2,3,4]
+Output: 10
+```
+
+Example 4:
+
+```c
+Input: [3,6,2,3]
+Output: 8
+```
+
+Note:
+
+- 3 <= A.length <= 10000
+- 1 <= A[i] <= 10^6
+
+## 题目大意
+
+找到可以组成三角形三条边的长度，要求输出三条边之和最长的，即三角形周长最长。
+
+这道题也是排序题，先讲所有的长度进行排序，从大边开始往前找，找到第一个任意两边之和大于第三边(满足能构成三角形的条件)的下标，然后输出这 3 条边之和即可，如果没有找到输出 0 。