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l414-third-maximum-number

admin 11月 13, 2020 0

题目描述

Given a non-empty array of integers, return the third maximum number in this array. If it does not exist, return the maximum number. The time complexity must be in O(n).

Example 1:
Input: [3, 2, 1]

Output: 1

Explanation: The third maximum is 1.
Example 2:
Input: [1, 2]

Output: 2

Explanation: The third maximum does not exist, so the maximum (2) is returned instead.
Example 3:
Input: [2, 2, 3, 1]

Output: 1

Explanation: Note that the third maximum here means the third maximum distinct number.
Both numbers with value 2 are both considered as second maximum.

解题思路

使用三个变量

Go代码

Go代码实现

import "math"

func (nums []int) int {
	ret := []int{math.MinInt64, math.MinInt64, math.MinInt64}

	for _,n := range nums{
		if n == ret[0] || n == ret[1] || n == ret[2] {
			continue
		}
		if n > ret[0]{
			ret = []int{n, ret[0], ret[1]}
		}else if n>ret[1] {
			ret = []int{ret[0], n, ret[1]}
		}else if n>ret[2]{
			ret = []int{ret[0], ret[1], n}
		}
	}
	if ret[2] == math.MinInt64{
		return ret[0]
	}else{
		return ret[2]
	}
}