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75 lines
1.7 KiB
Markdown
75 lines
1.7 KiB
Markdown
# [747. Largest Number At Least Twice of Others](https://leetcode.com/problems/largest-number-at-least-twice-of-others/)
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## 题目
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You are given an integer array `nums` where the largest integer is **unique**.
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Determine whether the largest element in the array is **at least twice** as much as every other number in the array. If it is, return *the **index** of the largest element, or return* `-1` *otherwise*.
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**Example 1:**
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```
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Input: nums = [3,6,1,0]
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Output: 1
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Explanation: 6 is the largest integer.
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For every other number in the array x, 6 is at least twice as big as x.
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The index of value 6 is 1, so we return 1.
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```
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**Example 2:**
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```
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Input: nums = [1,2,3,4]
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Output: -1
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Explanation: 4 is less than twice the value of 3, so we return -1.
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```
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**Example 3:**
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```
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Input: nums = [1]
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Output: 0
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Explanation: 1 is trivially at least twice the value as any other number because there are no other numbers.
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```
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**Constraints:**
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- `1 <= nums.length <= 50`
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- `0 <= nums[i] <= 100`
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- The largest element in `nums` is unique.
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## 题目大意
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给你一个整数数组 nums ，其中总是存在 唯一的 一个最大整数 。请你找出数组中的最大元素并检查它是否 至少是数组中每个其他数字的两倍 。如果是，则返回 最大元素的下标 ，否则返回 -1 。
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## 解题思路
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- 简单题。先扫描一遍找到最大值和下标。再扫描一遍检查最大值是否是其他数字的两倍。
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## 代码
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```go
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package leetcode
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func dominantIndex(nums []int) int {
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maxNum, flag, index := 0, false, 0
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for i, v := range nums {
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if v > maxNum {
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maxNum = v
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index = i
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}
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}
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for _, v := range nums {
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if v != maxNum && 2*v > maxNum {
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flag = true
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}
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}
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if flag {
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return -1
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}
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return index
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}
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``` |