Given an array of characters, compress it in-place.
The length after compression must always be smaller than or equal to the original array.
Every element of the array should be a character (not int) of length 1.
After you are done modifying the input array in-place, return the new length of the array.
Follow up:
Could you solve it using only O(1) extra space?
Example 1:
Input:
["a","a","b","b","c","c","c"]
Output:
Return 6, and the first 6 characters of the input array should be: ["a","2","b","2","c","3"]
Explanation:
"aa" is replaced by "a2". "bb" is replaced by "b2". "ccc" is replaced by "c3".
Example 2:
Input:
["a"]
Output:
Return 1, and the first 1 characters of the input array should be: ["a"]
Explanation:
Nothing is replaced.
Example 3:
Input:
["a","b","b","b","b","b","b","b","b","b","b","b","b"]
Output:
Return 4, and the first 4 characters of the input array should be: ["a","b","1","2"].
Explanation:
Since the character "a" does not repeat, it is not compressed. "bbbbbbbbbbbb" is replaced by "b12".
Notice each digit has it's own entry in the array.
Note:
- All characters have an ASCII value in [35, 126].
- 1 <= len(chars) <= 1000.
这题思路挺容易的，坑爹的地方是，go无法缩减传入的slice的长度，只能是半成品了。
func compress(chars []byte) int {
var current byte
var count int
var index int // 指向chars中需要修改的位置
for k, v := range chars {
count++
if v != current || k == len(chars)-1 {
if current != 0 {
chars[index] = current
index++
if count > 1 {
if k == len(chars)-1 {
count++
}
chars[index] = byte(count - 1 + 48)
index++
}
current = v
count = 1
continue
}
current = v
}
}
// chars = chars[:index] // not work
// fmt.Println(string(chars))
// copy(chars, chars[:index]) // not work
// chars = append([]byte{}, chars[:index]...)
temp := make([]byte, 0)
copy(temp, chars[:index])
chars = make([]byte, 0, 0)
chars = append(chars, temp...)
return index
}