给定一个字符串,按降序对其进行排序。
例子:
Input : alkasingh
Output : snlkihgaa
Input : nupursingh
Output : uusrpnnihg
Input : geeksforgeeks
Output : ssrokkggfeeee
一个简单的解决方案是使用库排序函数std::sort()
C++
// CPP program to sort a string in descending
// order using library function
#include
using namespace std;
void descOrder(string s)
{
sort(s.begin(), s.end(), greater());
}
int main()
{
string s = "geeksforgeeks";
descOrder(s); // function call
return 0;
}
Java
// Java program to sort a string in descending
// order using library function
import java.util.*;
class GFG
{
static void descOrder(char[] s)
{
Arrays.sort(s);
reverse(s);
}
static void reverse(char[] a)
{
int i, n = a.length;
char t;
for (i = 0; i < n / 2; i++)
{
t = a[i];
a[i] = a[n - i - 1];
a[n - i - 1] = t;
}
}
// Driver code
public static void main(String[] args)
{
char[] s = "geeksforgeeks".toCharArray();
descOrder(s); // function call
System.out.println(String.valueOf(s));
}
}
// This code is contributed by 29AjayKumar
Python
# Python program to sort
# a string in descending
# order using library function
def descOrder(s):
s.sort(reverse = True)
str1 = ''.join(s)
print(str1)
def main():
s = list('geeksforgeeks')
# function call
descOrder(s)
if __name__=="__main__":
main()
# This code is contributed by
# prabhat kumar singh
C#
// C# program to sort a string in descending
// order using library function
using System;
class GFG
{
static void descOrder(char[] s)
{
Array.Sort(s);
reverse(s);
}
static void reverse(char[] a)
{
int i, n = a.Length;
char t;
for (i = 0; i < n / 2; i++)
{
t = a[i];
a[i] = a[n - i - 1];
a[n - i - 1] = t;
}
}
// Driver code
public static void Main(String[] args)
{
char[] s = "geeksforgeeks".ToCharArray();
descOrder(s); // function call
Console.WriteLine(String.Join("",s));
}
}
// This code is contributed by Rajput-Ji
PHP
Javascript
C++
// C++ program to sort a string of characters
// in descending order
#include
using namespace std;
const int MAX_CHAR = 26;
// function to print string in sorted order
void sortString(string& str)
{
// Hash array to keep count of characters.
// Initially count of all charters is
// initialized to zero.
int charCount[MAX_CHAR] = { 0 };
// Traverse string and increment
// count of characters
for (int i = 0; i < str.length(); i++)
// 'a'-'a' will be 0, 'b'-'a' will be 1,
// so for location of character in count
// array we wil do str[i]-'a'.
charCount[str[i] - 'a']++;
// Traverse the hash array and print
// characters
for (int i = MAX_CHAR - 1; i >= 0; i--)
for (int j = 0; j < charCount[i]; j++)
cout << (char)('a' + i);
}
// Driver program to test above function
int main()
{
string s = "alkasingh";
sortString(s);
return 0;
}
Java
// Java program to sort a string of characters
// in descending order
class GFG
{
static int MAX_CHAR = 26;
// function to print string in sorted order
static void sortString(String str)
{
// Hash array to keep count of characters.
// Initially count of all charters is
// initialized to zero.
int charCount[] = new int[MAX_CHAR];
// Traverse string and increment
// count of characters
// 'a'-'a' will be 0, 'b'-'a' will be 1,
for (int i = 0; i < str.length(); i++)
{
// so for location of character in count
// array we wil do str[i]-'a'.
charCount[str.charAt(i) - 'a']++;
}
// Traverse the hash array and print
// characters
for (int i = MAX_CHAR - 1; i >= 0; i--)
{
for (int j = 0; j < charCount[i]; j++)
{
System.out.print((char) ('a' + i));
}
}
}
// Driver code
public static void main(String[] args)
{
String s = "alkasingh";
sortString(s);
}
}
// This code is contributed by 29AjayKumar
Python3
# Python program to sort a string of characters
# in descending order
MAX_CHAR = 26;
# function to print string in sorted order
def sortString(str):
# Hash array to keep count of characters.
# Initially count of all charters is
# initialized to zero.
charCount = [0]*MAX_CHAR;
# Traverse string and increment
# count of characters
for i in range(len(str)):
# 'a'-'a' will be 0, 'b'-'a' will be 1,
# so for location of character in count
# array we wil do str[i]-'a'.
charCount[ord(str[i]) - ord('a')]+=1;
# Traverse the hash array and print
# characters
for i in range(MAX_CHAR - 1,-1, -1):
for j in range(charCount[i]):
print(chr(97+i),end="");
# Driver program to test above function
s = "alkasingh";
sortString(s);
# This code is contributed by Princi Singh
C#
// C# program to sort a string of characters
// in descending order
using System;
class GFG
{
static int MAX_CHAR = 26;
// function to print string in sorted order
static void sortString(String str)
{
// Hash array to keep count of characters.
// Initially count of all charters is
// initialized to zero.
int []charCount = new int[MAX_CHAR];
// Traverse string and increment
// count of characters
// 'a'-'a' will be 0, 'b'-'a' will be 1,
for (int i = 0; i < str.Length; i++)
{
// so for location of character in
// count array we wil do str[i]-'a'.
charCount[str[i] - 'a']++;
}
// Traverse the hash array and print
// characters
for (int i = MAX_CHAR - 1; i >= 0; i--)
{
for (int j = 0; j < charCount[i]; j++)
{
Console.Write((char) ('a' + i));
}
}
}
// Driver code
public static void Main(String[] args)
{
String s = "alkasingh";
sortString(s);
}
}
// This code is contributed by PrinciRaj1992
Javascript
输出:
ssrokkggfeeee
时间复杂度为:O(n log n)
一种有效的方法是首先观察总共只能有 26 个唯一字符。因此,我们可以将从 ‘a’ 到 ‘z’ 的所有字符出现的次数存储在一个散列数组中。散列数组的第一个索引将代表字符“a”,第二个将代表“b”,依此类推。最后,我们将简单地遍历散列数组并打印“Z”的字符“A”,他们在输入字符串出现的次数。
下面是上述想法的实现:
C++
// C++ program to sort a string of characters
// in descending order
#include
using namespace std;
const int MAX_CHAR = 26;
// function to print string in sorted order
void sortString(string& str)
{
// Hash array to keep count of characters.
// Initially count of all charters is
// initialized to zero.
int charCount[MAX_CHAR] = { 0 };
// Traverse string and increment
// count of characters
for (int i = 0; i < str.length(); i++)
// 'a'-'a' will be 0, 'b'-'a' will be 1,
// so for location of character in count
// array we wil do str[i]-'a'.
charCount[str[i] - 'a']++;
// Traverse the hash array and print
// characters
for (int i = MAX_CHAR - 1; i >= 0; i--)
for (int j = 0; j < charCount[i]; j++)
cout << (char)('a' + i);
}
// Driver program to test above function
int main()
{
string s = "alkasingh";
sortString(s);
return 0;
}
Java
// Java program to sort a string of characters
// in descending order
class GFG
{
static int MAX_CHAR = 26;
// function to print string in sorted order
static void sortString(String str)
{
// Hash array to keep count of characters.
// Initially count of all charters is
// initialized to zero.
int charCount[] = new int[MAX_CHAR];
// Traverse string and increment
// count of characters
// 'a'-'a' will be 0, 'b'-'a' will be 1,
for (int i = 0; i < str.length(); i++)
{
// so for location of character in count
// array we wil do str[i]-'a'.
charCount[str.charAt(i) - 'a']++;
}
// Traverse the hash array and print
// characters
for (int i = MAX_CHAR - 1; i >= 0; i--)
{
for (int j = 0; j < charCount[i]; j++)
{
System.out.print((char) ('a' + i));
}
}
}
// Driver code
public static void main(String[] args)
{
String s = "alkasingh";
sortString(s);
}
}
// This code is contributed by 29AjayKumar
蟒蛇3
# Python program to sort a string of characters
# in descending order
MAX_CHAR = 26;
# function to print string in sorted order
def sortString(str):
# Hash array to keep count of characters.
# Initially count of all charters is
# initialized to zero.
charCount = [0]*MAX_CHAR;
# Traverse string and increment
# count of characters
for i in range(len(str)):
# 'a'-'a' will be 0, 'b'-'a' will be 1,
# so for location of character in count
# array we wil do str[i]-'a'.
charCount[ord(str[i]) - ord('a')]+=1;
# Traverse the hash array and print
# characters
for i in range(MAX_CHAR - 1,-1, -1):
for j in range(charCount[i]):
print(chr(97+i),end="");
# Driver program to test above function
s = "alkasingh";
sortString(s);
# This code is contributed by Princi Singh
C#
// C# program to sort a string of characters
// in descending order
using System;
class GFG
{
static int MAX_CHAR = 26;
// function to print string in sorted order
static void sortString(String str)
{
// Hash array to keep count of characters.
// Initially count of all charters is
// initialized to zero.
int []charCount = new int[MAX_CHAR];
// Traverse string and increment
// count of characters
// 'a'-'a' will be 0, 'b'-'a' will be 1,
for (int i = 0; i < str.Length; i++)
{
// so for location of character in
// count array we wil do str[i]-'a'.
charCount[str[i] - 'a']++;
}
// Traverse the hash array and print
// characters
for (int i = MAX_CHAR - 1; i >= 0; i--)
{
for (int j = 0; j < charCount[i]; j++)
{
Console.Write((char) ('a' + i));
}
}
}
// Driver code
public static void Main(String[] args)
{
String s = "alkasingh";
sortString(s);
}
}
// This code is contributed by PrinciRaj1992
Javascript
输出:
snlkihgaa
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