给定字符串字符。任务是编写一个程序，以使用堆栈按排序顺序打印此字符串的字符。
例子：
Input: str = "geeksforgeeks"
Output: eeeefggkkorss
Input: str = "hello395world216"
Output: 123569dehllloorw方法：
- 初始化两个堆栈，一个堆栈和另一个tempstack 。
- 将字符串的第一个字符插入堆栈中。
- 迭代字符串的所有字符
- 如果第i个字符大于或等于堆栈的顶部元素，则推入该元素。
- 如果第i个字符不大，则将堆栈的所有元素压入tempstack ，然后将字符压入堆栈。之后，将tempstack的所有更大元素推入stack 。
迭代完成后，以相反的顺序打印堆栈中的所有元素。
下面是上述方法的实现：
C++
// C++ program to sort string of
// characters using stack
#include
using namespace std;
// Function to print the characters
// in sorted order
void printSorted(string s, int l)
{
// Primary stack
stack Stack;
// Secondary stack
stack tempstack;
// Append first character
Stack.push(s[0]);
// Iterate for all character in string
for(int i = 1; i < l; i++)
{
// i-th character ASCII
int a = s[i];
// stack's top element ASCII
int b = Stack.top();
// If greater or equal to top element
// then push to stack
if ((a - b) >= 1 or (a == b))
Stack.push(s[i]);
// If smaller, then push all element
// to the temporary stack
else if ((b - a) >= 1)
{
// Push all greater elements
while ((b - a) >= 1)
{
// Push operation
tempstack.push(Stack.top());
Stack.pop();
// Push till the stack is not-empty
if (Stack.size() > 0)
b = Stack.top();
else
break;
}
// Push the i-th character
Stack.push(s[i]);
// Push the tempstack back to stack
while (tempstack.size() > 0)
{
Stack.push(tempstack.top());
tempstack.pop();
}
}
}
// Print the stack in reverse order
string answer;
while (Stack.size() > 0)
{
answer = Stack.top() + answer;
Stack.pop();
}
cout << answer << endl;
}
// Driver Code
int main()
{
string s = "geeksforgeeks";
int l = s.length();
printSorted(s, l);
return 0;
}
// This code is contributed by divyeshrabadiya07 Java
// Java program to sort string of
// characters using stack
import java.io.*;
import java.util.*;
class GFG{
// Function to print the characters
// in sorted order
public static void printSorted(String s,int l)
{
// Primary stack
Stack stack = new Stack();
// Secondary stack
Stack tempstack = new Stack();
// Append first character
stack.push(s.charAt(0));
// Iterate for all character in string
for(int i = 1; i < l; i++)
{
// i-th character ASCII
int a = s.charAt(i);
// Stack's top element ASCII
int b = (int)((char)stack.peek());
// If greater or equal to top element
// then push to stack
if ((a - b) >= 1 || (a == b))
{
stack.push(s.charAt(i));
}
// If smaller, then push all element
// to the temporary stack
else if ((b - a) >= 1)
{
// Push all greater elements
while ((b - a) >= 1)
{
// Push operation
tempstack.push(stack.peek());
stack.pop();
// Push till the stack is not-empty
if (stack.size() > 0)
{
b = (int)((char)stack.peek());
}
else
{
break;
}
}
// Push the i-th character
stack.push(s.charAt(i));
// Push the tempstack back to stack
while (tempstack.size() > 0)
{
stack.push(tempstack.peek());
tempstack.pop();
}
}
}
// Print the stack in reverse order
String answer = "";
while (stack.size() > 0)
{
answer = stack.peek()+answer;
stack.pop();
}
System.out.println(answer);
}
// Driver Code
public static void main(String []args)
{
String s = "geeksforgeeks";
int l = s.length();
printSorted(s, l);
}
}
// This code is contributed by rag2127 Python3
# Python3 program to sort
# string of characters using stack
# function to print the characters
# in sorted order
def printSorted(s, l):
# primary stack
stack =[]
# secondary stack
tempstack =[]
# append first character
stack.append(s[0])
# iterate for all character in string
for i in range(1, l):
# i-th character ASCII
a = ord(s[i])
# stack's top element ASCII
b = ord(stack[-1])
# if greater or equal to top element
# then push to stack
if((a-b)>= 1 or (a == b)):
stack.append(s[i])
# if smaller, then push all element
# to the temporary stack
elif((b-a)>= 1):
# push all greater elements
while((b-a)>= 1):
# push operation
tempstack.append(stack.pop())
# push till the stack is not-empty
if(len(stack)>0):
b = ord(stack[-1])
else:
break
# push the i-th character
stack.append(s[i])
# push the tempstack back to stack
while(len(tempstack)>0):
stack.append(tempstack.pop())
# print the stack in reverse order
print(''.join(stack))
# Driver Code
s = "geeksforgeeks"
l = len(s)
printSorted(s, l)C#
// C# program to sort string of
// characters using stack
using System;
using System.Collections;
class GFG {
// Function to print the characters
// in sorted order
static void printSorted(string s, int l)
{
// Primary stack
Stack stack = new Stack();
// Secondary stack
Stack tempstack = new Stack();
// Append first character
stack.Push(s[0]);
// Iterate for all character in string
for(int i = 1; i < l; i++)
{
// i-th character ASCII
int a = s[i];
// stack's top element ASCII
int b = (int)((char)stack.Peek());
// If greater or equal to top element
// then push to stack
if ((a - b) >= 1 || (a == b))
stack.Push(s[i]);
// If smaller, then push all element
// to the temporary stack
else if ((b - a) >= 1)
{
// Push all greater elements
while ((b - a) >= 1)
{
// Push operation
tempstack.Push(stack.Peek());
stack.Pop();
// Push till the stack is not-empty
if (stack.Count > 0)
b = (int)((char)stack.Peek());
else
break;
}
// Push the i-th character
stack.Push(s[i]);
// Push the tempstack back to stack
while (tempstack.Count > 0)
{
stack.Push(tempstack.Peek());
tempstack.Pop();
}
}
}
// Print the stack in reverse order
string answer = "";
while (stack.Count > 0)
{
answer = stack.Peek() + answer;
stack.Pop();
}
Console.WriteLine(answer);
}
static void Main() {
string s = "geeksforgeeks";
int l = s.Length;
printSorted(s, l);
}
}
// This code is contributed by divyesh072019输出：
eeeefggkkorss这篇文章中已经实现了一种使用哈希的有效方法