Leetcode 344.Reverse String

Test instructions

Write a function that takes a string as input and returns the string reversed. Example: Given s = "Hello", Return "Olleh".

Implements the reversal of a string.

At first, I was the direct string fan, and then I gave the fan a value, and I found that the output was an empty string. The solution is not to be baffled. Then use char fan[length], and then assign the value to get the result of the reversal. However, less consideration is given to the incorrect output when the s= "" is turned on. The error is then corrected, the fan is initialized to S, and then reversed with a for loop to get the correct answer. The code is as follows:

class Solution {public:    string reversestring (string  s) {         int length = s.length ();         string fan = s;          for (int0; i < length; i++)         = s[length-1-i];         return fan;    }};

The efficiency diagram for the code is as follows:

Sure enough, the method is not very efficient.

After thinking that the reverse function in the string library might be better and more efficient, the code is written as follows:

class Solution {public:    string reversestring (string  s) {        Reverse (S.begin (), S.end ());         return s;    }};

The code is really short, but the efficiency is not improved, or as with the For loop, the reverse function may also be written in a loop.

Then think of the loop that can be cut in half short:

class Solution {public:    string reversestring (string  s) {         int length = s.length ();          for (int0; i < length/2 ; i++)        swap (s[i],s[length-1- i]);         return s;    }};

However, the effect is not ideal, or the same as the original.

Looking at discuss, I found that most of the answers were the same.

Summarize:

This problem consolidates the knowledge of string, which was previously thought to directly modify data of type string.

Leetcode 344.Reverse String