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This approach involves splitting the original string into individual words using space as a delimiter, reversing the list of words, and then joining them back together with a single space.
Time Complexity: O(N), where N is the length of the string, as we process each character once.
Space Complexity: O(N), additional space for intermediate and result storage.
1#include <stdio.h>
2#include <string.h>
3#include <stdlib.h>
4
5char* reverseWords(char *s) {
6 // calculate length
7 int len = strlen(s), start = 0, wordCount = 0;
8 char *temp = malloc(len + 1);
9 char *result = malloc(len + 1);
10 temp[0] = '\0'; result[0] = '\0';
11
12 // trim leading and trailing spaces
13 while (s[start] == ' ') start++;
14 int end = len - 1;
15 while (s[end] == ' ') end--;
16
17 for (int i = start; i <= end; i++) {
18 if (s[i] != ' ') {
19 strncat(temp, &s[i], 1);
20 } else if (s[i] == ' ' && (i == start || s[i - 1] != ' ')) {
21 strcat(temp, " ");
22 }
23 }
24 char *token = strtok(temp, " ");
25 while (token != NULL) {
26 if (wordCount > 0) {
27 memmove(result + strlen(token) + 1, result, strlen(result) + 1);
28 memcpy(result, " ", 1);
29 }
30 memmove(result + strlen(token), result, strlen(result) + 1);
31 memcpy(result, token, strlen(token));
32 token = strtok(NULL, " ");
33 wordCount++;
34 }
35 free(temp);
36 return result;
37}
38
39int main() {
40 char input[] = " hello world ";
41 char* output = reverseWords(input);
42 printf("%s\n", output);
43 free(output);
44 return 0;
45}The C solution involves:
strtok() to split the string by spaces into separate words.This optimized approach manipulates the string in place by using a character array. We'll first reverse the entire string, and then reverse each word to return them to their correct order.
Time Complexity: O(N), where N is the number of characters in the string.
Space Complexity: O(1), as the operation is done in-place without extra space.
1function
JavaScript approach includes trimming the string, reversing the entire string, and then dealing with reversals of each individuated word in place for the final output format.