Description
Given a string s, return the number of segments in the string.
A segment is defined to be a contiguous sequence of non-space characters.
Example 1:
Input: s = "Hello, my name is John"
Output: 5
Explanation: The five segments are ["Hello,", "my", "name", "is", "John"]
Example 2:
Input: s = "Hello"
Output: 1
Constraints:
0 <= s.length <= 300s consists of lowercase and uppercase English letters, digits, or one of the following characters "!@#$%^&*()_+-=',.:".- The only space character in
s is ' '.
Solutions
Solution 1: String Splitting
We split the string s by spaces and then count the number of non-empty words.
The time complexity is O(n), and the space complexity is O(n), where n is the length of the string s.
PythonJavaC++GoTypeScriptPHP
class Solution:
def countSegments(self, s: str) -> int:
return len(s.split())(code-box)
class Solution {
public int countSegments(String s) {
int ans = 0;
for (String t : s.split(" ")) {
if (!"".equals(t)) {
++ans;
}
}
return ans;
}
}(code-box)
class Solution {
public:
int countSegments(string s) {
int ans = 0;
istringstream ss(s);
while (ss >> s) ++ans;
return ans;
}
};(code-box)
func countSegments(s string) int {
ans := 0
for _, t := range strings.Split(s, " ") {
if len(t) > 0 {
ans++
}
}
return ans
}(code-box)
function countSegments(s: string): number {
return s.split(/\s+/).filter(Boolean).length;
}(code-box)
class Solution {
/**
* @param String $s
* @return Integer
*/
function countSegments($s) {
$arr = explode(' ', $s);
$cnt = 0;
for ($i = 0; $i < count($arr); $i++) {
if (strlen($arr[$i]) != 0) {
$cnt++;
}
}
return $cnt;
}
}(code-box)
Solution 2: Simulation
We can also directly traverse each character s[i] in the string. If s[i] is not a space and s[i-1] is a space or i = 0, then s[i] marks the beginning of a new word, and we increment the answer by one.
After the traversal, we return the answer.
The time complexity is O(n), where n is the length of the string s. The space complexity is O(1).
PythonJavaC++GoTypeScriptPHP
class Solution:
def countSegments(self, s: str) -> int:
ans = 0
for i, c in enumerate(s):
if c != ' ' and (i == 0 or s[i - 1] == ' '):
ans += 1
return ans(code-box)
class Solution {
public int countSegments(String s) {
int ans = 0;
for (int i = 0; i < s.length(); ++i) {
if (s.charAt(i) != ' ' && (i == 0 || s.charAt(i - 1) == ' ')) {
++ans;
}
}
return ans;
}
}(code-box)
class Solution {
public:
int countSegments(string s) {
int ans = 0;
for (int i = 0; i < s.size(); ++i) {
if (s[i] != ' ' && (i == 0 || s[i - 1] == ' ')) {
++ans;
}
}
return ans;
}
};(code-box)
func countSegments(s string) int {
ans := 0
for i, c := range s {
if c != ' ' && (i == 0 || s[i-1] == ' ') {
ans++
}
}
return ans
}(code-box)
function countSegments(s: string): number {
let ans = 0;
for (let i = 0; i < s.length; i++) {
let c = s[i];
if (c !== ' ' && (i === 0 || s[i - 1] === ' ')) {
ans++;
}
}
return ans;
}(code-box)
class Solution {
/**
* @param String $s
* @return Integer
*/
function countSegments($s) {
$ans = 0;
$n = strlen($s);
for ($i = 0; $i < $n; $i++) {
$c = $s[$i];
if ($c !== ' ' && ($i === 0 || $s[$i - 1] === ' ')) {
$ans++;
}
}
return $ans;
}
}(code-box)
