Reverse Words - Amazon Top Interview Questions


Problem Statement :


Given a string s of words delimited by spaces, reverse the order of words.

Constraints

n ≤ 100,000 where n is the length of s


Example 1

Input
sentence = "hello there my friend"


Output
"friend my there hello"


Solution :



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                        Solution in C++ :

string solve(string sentence) {
    int N = sentence.size();
    for (int i = 0, j = 0; i < N;) {
        while (i < N && isspace(sentence[i])) i++;
        if (i >= N) break;
        for (j = i; j < N && !isspace(sentence[j]); j++)
            ;
        reverse(sentence.begin() + i, sentence.begin() + j);
        i = j;
    }
    reverse(sentence.begin(), sentence.end());
    return sentence;
}
                    

                        Solution in Java :

import java.util.*;

class Solution {
    public String solve(String s) {
        String temp = "";
        String res = "";

        for (int i = 0; i < s.length(); i++) {
            char c = s.charAt(i);
            if ((int) c == 32) {
                res = " " + temp + res;
                temp = "";
            } else {
                temp = temp + c;
            }
        }
        res = temp + res;
        return res;
    }
}
                    

                        Solution in Python : 
                            
class Solution:
    def solve(self, sentence):
        s = sentence.split(" ")
        s = s[::-1]
        return " ".join(s)
                    

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