mirror of
https://github.com/halfrost/LeetCode-Go.git
synced 2025-07-05 16:36:41 +08:00
70 lines
1.9 KiB
Markdown
70 lines
1.9 KiB
Markdown
# [1758. Minimum Changes To Make Alternating Binary String](https://leetcode.com/problems/minimum-changes-to-make-alternating-binary-string/)
|
||
|
||
|
||
## 题目
|
||
|
||
You are given a string `s` consisting only of the characters `'0'` and `'1'`. In one operation, you can change any `'0'` to `'1'` or vice versa.
|
||
|
||
The string is called alternating if no two adjacent characters are equal. For example, the string `"010"` is alternating, while the string `"0100"` is not.
|
||
|
||
Return *the **minimum** number of operations needed to make* `s` *alternating*.
|
||
|
||
**Example 1:**
|
||
|
||
```
|
||
Input: s = "0100"
|
||
Output: 1
|
||
Explanation: If you change the last character to '1', s will be "0101", which is alternating.
|
||
```
|
||
|
||
**Example 2:**
|
||
|
||
```
|
||
Input: s = "10"
|
||
Output: 0
|
||
Explanation: s is already alternating.
|
||
```
|
||
|
||
**Example 3:**
|
||
|
||
```
|
||
Input: s = "1111"
|
||
Output: 2
|
||
Explanation: You need two operations to reach "0101" or "1010".
|
||
```
|
||
|
||
**Constraints:**
|
||
|
||
- `1 <= s.length <= 104`
|
||
- `s[i]` is either `'0'` or `'1'`.
|
||
|
||
## 题目大意
|
||
|
||
你将得到一个仅包含字符“ 0”和“ 1”的字符串 `s`。 在一项操作中，你可以将任何 `'0'` 更改为 `'1'`，反之亦然。 如果两个相邻字符都不相等，则该字符串称为交替字符串。 例如，字符串“ 010”是交替的，而字符串“ 0100”则不是。 返回使 `s` 交替所需的最小操作数。
|
||
|
||
## 解题思路
|
||
|
||
- 简单题。利用数组下标奇偶交替性来判断交替字符串。交替字符串有 2 种，一个是 `'01010101……'` 还有一个是 `'1010101010……'`，这两个只需要计算出一个即可，另外一个利用 `len(s) - res` 就是答案。
|
||
|
||
## 代码
|
||
|
||
```go
|
||
package leetcode
|
||
|
||
func minOperations(s string) int {
|
||
res := 0
|
||
for i := 0; i < len(s); i++ {
|
||
if int(s[i]-'0') != i%2 {
|
||
res++
|
||
}
|
||
}
|
||
return min(res, len(s)-res)
|
||
}
|
||
|
||
func min(a, b int) int {
|
||
if a > b {
|
||
return b
|
||
}
|
||
return a
|
||
}
|
||
``` |