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49 lines
962 B
Markdown
49 lines
962 B
Markdown
# [976. Largest Perimeter Triangle](https://leetcode.com/problems/largest-perimeter-triangle/)
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## 题目
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Given an array A of positive lengths, return the largest perimeter of a triangle with non-zero area, formed from 3 of these lengths.
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If it is impossible to form any triangle of non-zero area, return 0.
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Example 1:
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```c
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Input: [2,1,2]
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Output: 5
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```
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Example 2:
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```c
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Input: [1,2,1]
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Output: 0
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```
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Example 3:
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```c
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Input: [3,2,3,4]
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Output: 10
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```
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Example 4:
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```c
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Input: [3,6,2,3]
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Output: 8
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```
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Note:
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- 3 <= A.length <= 10000
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- 1 <= A[i] <= 10^6
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## 题目大意
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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。
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## 解题思路
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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 。 |