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101 lines
2.4 KiB
Markdown
101 lines
2.4 KiB
Markdown
# [2165. Smallest Value of the Rearranged Number](https://leetcode.com/problems/smallest-value-of-the-rearranged-number/)
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## 题目
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You are given an integer `num.` **Rearrange** the digits of `num` such that its value is **minimized** and it does not contain **any** leading zeros.
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Return *the rearranged number with minimal value*.
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Note that the sign of the number does not change after rearranging the digits.
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**Example 1:**
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```
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Input: num = 310
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Output: 103
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Explanation: The possible arrangements for the digits of 310 are 013, 031, 103, 130, 301, 310.
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The arrangement with the smallest value that does not contain any leading zeros is 103.
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```
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**Example 2:**
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```
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Input: num = -7605
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Output: -7650
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Explanation: Some possible arrangements for the digits of -7605 are -7650, -6705, -5076, -0567.
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The arrangement with the smallest value that does not contain any leading zeros is -7650.
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```
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**Constraints:**
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- `10^15 <= num <= 10^15`
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## 题目大意
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给你一个整数 num 。重排 num 中的各位数字，使其值 最小化 且不含 任何 前导零。
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返回不含前导零且值最小的重排数字。注意，重排各位数字后，num 的符号不会改变。
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## 解题思路
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- 先将每个数字出现次数统计出来。然后将数字大小从小到大排序。如果原数是正数，当出现有数字 0 的情况的时候，需先将第二小的数字排列到第一个，再把 0 排列完。再继续排列第二小，第三小。。。
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- 如果原数是负数。那么就逆序排列，即先排列最大的数字，然后次大的数字，直到排列最小的数字。因为数字越大，对应的这个数的负数就越小。
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## 代码
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```go
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package leetcode
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import "sort"
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func smallestNumber(num int64) int64 {
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pos := true
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if num < 0 {
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pos = false
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num *= -1
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}
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nums, m, res := []int{}, map[int]int{}, 0
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for num != 0 {
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tmp := int(num % 10)
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m[tmp]++
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num = num / 10
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}
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for k := range m {
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nums = append(nums, k)
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}
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if pos {
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sort.Ints(nums)
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} else {
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sort.Sort(sort.Reverse(sort.IntSlice(nums)))
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}
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if nums[0] == 0 && len(nums) > 1 {
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res += nums[1]
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m[nums[1]]--
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}
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for _, v := range nums {
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if res != 0 {
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for j := m[v]; j > 0; j-- {
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res = res * 10
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res += v
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}
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} else {
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res += v
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tmp := m[v] - 1
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for j := tmp; j > 0; j-- {
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res = res * 10
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res += v
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}
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}
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}
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if !pos {
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return -1 * int64(res)
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}
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return int64(res)
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}
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``` |