检查是否给定的字符串的字符是按字母顺序排列

给定一个字符串“S”，任务是寻找如果字符串的字符是字母顺序排列。该字符串仅包含小写字符。
例子：

Input: Str = "aabbbcc"
Output: In alphabetical order

Input: Str = "aabbbcca"
Output: Not in alphabetical order

一种简单的方法：

• 将字符串存储到字符数组并对该数组进行排序。
• 如果排序数组中的字符与字符串的顺序相同，则打印“按字母顺序”。
• 否则，打印“不是按字母顺序排列”。

下面是上述方法的实现：

C++

// C++ implementation of above approach
#include 
using namespace std;
 
// Function that checks whether
// the string is in alphabetical
// order or not
bool isAlphabaticOrder(string s)
{
    // length of the string
    int n = s.length();
 
    // create a character array
    // of the length of the string
    char c[n];
 
    // assign the string
    // to character array
    for (int i = 0; i < n; i++) {
        c[i] = s[i];
    }
 
    // sort the character array
    sort(c, c + n);
 
    // check if the character array
    // is equal to the string or not
    for (int i = 0; i < n; i++)
        if (c[i] != s[i])
            return false;
         
    return true;   
}
 
// Driver code
int main()
{
    string s = "aabbbcc";
 
    // check whether the string is
    // in alphabetical order or not
    if (isAlphabaticOrder(s))
       cout << "Yes";
    else
       cout << "No";
 
    return 0;
}

Java

// Java implementation of above approach
 
// import  Arrays class
import java.util.Arrays;
 
public class GFG {
 
    // Function that checks whether
    // the string is in alphabetical
    // order or not
    static boolean isAlphabaticOrder(String s)
    {
        // length of the string
        int n = s.length();
       
        // create a character array
        // of the length of the string
        char c[] = new char [n];
       
        // assign the string
        // to character array
        for (int i = 0; i < n; i++) {
            c[i] = s.charAt(i);
        }
       
        // sort the character array
        Arrays.sort(c);
       
        // check if the character array
        // is equal to the string or not
        for (int i = 0; i < n; i++)
            if (c[i] != s.charAt(i)) 
                return false;
               
        return true;    
    }
     
    public static void main(String args[])
    {
        String s = "aabbbcc";
         
        // check whether the string is
        // in alphabetical order or not
        if (isAlphabaticOrder(s))
           System.out.println("Yes");
        else
            System.out.println("No");
           
    }
    // This Code is contributed by ANKITRAI1
}

Python3

# Python 3 implementation of above approach
 
# Function that checks whether
# the string is in alphabetical
# order or not
def isAlphabaticOrder(s):
     
    # length of the string
    n = len(s)
 
    # create a character array
    # of the length of the string
    c = [s[i] for i in range(len(s))]
 
    # sort the character array
    c.sort(reverse = False)
 
    # check if the character array
    # is equal to the string or not
    for i in range(n):
        if (c[i] != s[i]):
            return False
         
    return True
 
# Driver code
if __name__ == '__main__':
    s = "aabbbcc"
 
    # check whether the string is
    # in alphabetical order or not
    if (isAlphabaticOrder(s)):
        print("Yes")
    else:
        print("No")
 
# This code is contributed by
# Surendra_Gangwar

C#

// C# implementation of above approach
// import Arrays class
 
using System;
 
public class GFG{
     
    // Function that checks whether
    // the string is in alphabetical
    // order or not
    static bool isAlphabaticOrder(String s)
    {
        // length of the string
        int n = s.Length;
     
        // create a character array
        // of the length of the string
        char []c = new char [n];
     
        // assign the string
        // to character array
        for (int i = 0; i < n; i++) {
            c[i] = s[i];
        }
     
        // sort the character array
        Array.Sort(c);
     
        // check if the character array
        // is equal to the string or not
        for (int i = 0; i < n; i++)
            if (c[i] != s[i])
                return false;
             
        return true;    
    }
     
    static public void Main (){
        String s = "aabbbcc";
         
        // check whether the string is
        // in alphabetical order or not
        if (isAlphabaticOrder(s))
        Console.WriteLine("Yes");
        else
            Console.WriteLine("No");
         
    }
}

输出：

Yes

时间复杂度： O(N * log(N))

辅助空间： O(N)
高效的方法：

• 运行从1到(n-1)的循环(其中n是字符串的长度)
• 检查索引“ i”处的元素是否小于索引“ i-1”处的元素。
• 如果是，则打印“按字母顺序”。
• 否则，打印“不是按字母顺序排列”。

下面是上述方法的实现

C++

// C++ implementation of above approach
#include 
using namespace std;
 
// Function that checks whether
// the string is in alphabetical
// order or not
bool isAlphabaticOrder(string s)
{
    int n = s.length();
 
    for (int i = 1; i < n; i++) {
 
        // if element at index 'i' is less
        // than the element at index 'i-1'
        // then the string is not sorted
        if (s[i] < s[i - 1])
           return false;
    }
 
    return true;
}
 
// Driver code
int main()
{
    string s = "aabbbcc";
 
    // check whether the string is
    // in alphabetical order or not
    if (isAlphabaticOrder(s))
       cout << "Yes";
    else
       cout << "No";
 
    return 0;
}

Java

// Java implementation of above approach
public class GFG {
 
// Function that checks whether
// the string is in alphabetical
// order or not
    static boolean isAlphabaticOrder(String s) {
        int n = s.length();
 
        for (int i = 1; i < n; i++) {
 
            // if element at index 'i' is less
            // than the element at index 'i-1'
            // then the string is not sorted
            if (s.charAt(i) < s.charAt(i - 1)) {
                return false;
            }
        }
 
        return true;
    }
 
// Driver code
    static public void main(String[] args) {
        String s = "aabbbcc";
        // check whether the string is
        // in alphabetical order or not
        if (isAlphabaticOrder(s)) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    }
}
//This code is contributed by PrinciRaj1992

的Python 3

# Python 3 implementation of above approach
 
# Function that checks whether
# the string is in alphabetical
# order or not
def isAlphabaticOrder(s):
 
    n = len(s)
 
    for i in range(1, n):
 
        # if element at index 'i' is less
        # than the element at index 'i-1'
        # then the string is not sorted
        if (s[i] < s[i - 1]) :
            return False
 
    return True
 
# Driver code
if __name__ == "__main__":
 
    s = "aabbbcc"
 
    # check whether the string is
    # in alphabetical order or not
    if (isAlphabaticOrder(s)):
        print("Yes")
    else:
        print("No")

C＃

// C# implementation of above approach
using System;
 
public class GFG{
     
// Function that checks whether
// the string is in alphabetical
// order or not
static bool isAlphabaticOrder(string s)
{
    int n = s.Length;
 
    for (int i = 1; i < n; i++) {
 
        // if element at index 'i' is less
        // than the element at index 'i-1'
        // then the string is not sorted
        if (s[i] < s[i - 1])
        return false;
    }
 
    return true;
}
 
// Driver code
    static public void Main (){
    string s = "aabbbcc";
    // check whether the string is
    // in alphabetical order or not
    if (isAlphabaticOrder(s))
    Console.WriteLine ("Yes");
        else
    Console.WriteLine  ("No");
    }
}

输出：

Yes

时间复杂度： O(N)
辅助空间： O(1)