Reverse Words In A String Problem
Description
LeetCode Problem 151.
Given an input string s, reverse the order of the words.
A word is defined as a sequence of non-space characters. The words in s will be separated by at least one space.
Return a string of the words in reverse order concatenated by a single space.
Note that s may contain leading or trailing spaces or multiple spaces between two words. The returned string should only have a single space separating the words. Do not include any extra spaces.
Example 1:
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Input: s = "the sky is blue"
Output: "blue is sky the"
Example 2:
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Input: s = " hello world "
Output: "world hello"
Explanation: Your reversed string should not contain leading or trailing spaces.
Example 3:
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Input: s = "a good example"
Output: "example good a"
Explanation: You need to reduce multiple spaces between two words to a single space in the reversed string.
Example 4:
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Input: s = " Bob Loves Alice "
Output: "Alice Loves Bob"
Example 5:
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Input: s = "Alice does not even like bob"
Output: "bob like even not does Alice"
Constraints:
- 1 <= s.length <= 10^4
- s contains English letters (upper-case and lower-case), digits, and spaces ‘ ‘.
- There is at least one word in s.
Sample C++ Code
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class Solution {
public:
void reverseword(string &s, int i, int j){
while(i<j){
char t=s[i];
s[i++]=s[j];
s[j--]=t;
}
}
void reverseWords(string &s) {
int i=0, j=0;
int l=0;
int len=s.length();
int wordcount=0;
while(true){
while(i<len && s[i] == ' ') i++;
if(i==len) break;
if(wordcount) s[j++]=' ';
l=j;
while(i<len && s[i] != ' ') {s[j]=s[i]; j++; i++;}
reverseword(s,l,j-1);
wordcount++;
}
s.resize(j);
reverseword(s,0,j-1);
}
};