使用条件交换对数组进行排序

给定一个数组arr包含从[1...到 n]的元素。每个元素在数组arr中只出现一次。给定一个长度为n-1的字符串str 。字符串的每个字符都是0或1 。在数组中，只要字符串的第 i 个字符是1 ，就可以将第i 个元素与第(i + 1) 个元素交换任意多次。我们的任务是找出是否可以按升序对数组进行排序。
例子：

Input : arr = {1, 2, 5, 3, 4, 6}
        str = "01110"
Output : Yes
Explanation :
Here, we can swap arr[2] and arr[3], and then 
swap arr[3] and arr[4].

Input : arr = {1, 2, 5, 3, 4, 6}
        str = "01010"
Output : No
Explanation :
Here, the 3rd element of the array i.e. 5 can not
be swapped as the 3rd character of the string is 0. 
Therefore it is impossible to sort the array.

方法对字符串str的长度运行一个循环，并为每个i计算从0到i的数组的max_element 。在每次迭代中，如果字符串的第 i 个字符为'0'并且max_element大于i + 1 ，则无法对数组进行排序，否则可能。
上述方法的基本实现：

C++

// CPP program to Check if it
// is possible to sort the
// array in ascending order.
#include 
using namespace std;
 
// Function to check if it is possible to
// sort the array
string possibleToSort(int* arr, int n, string str)
{
    int max_element = -1;
    for (long i = 0; i < str.size(); i++) {
 
        // Calculating max_element
        // at each iteration.
        max_element = max(max_element, arr[i]);
 
        // if we can not swap the i-th element.
        if (str[i] == '0') {
 
            // if it is impossible to swap the
            // max_element then we can not
            // sort the array.
            if (max_element > i + 1)
                return "No";
        }
    }
 
    // Otherwise, we can sort the array.
    return "Yes";
}
 
// Driver function
int main()
{
    int arr[] = { 1, 2, 5, 3, 4, 6 };
    int n = sizeof(arr) / sizeof(arr[0]);
    string str = "01110";
    cout << possibleToSort(arr, n, str);
    return 0;
}

Java

// Java program to Check if it is possible to
// sort the array in ascending order.
import java.util.*;
import java.lang.*;
 
// Function to check if it is possible to
// sort the array
class GFG
{
 
    public static String possibleToSort(int arr[],
                                int n, String str)
    {
 
        int max_element = -1;
        for (int i = 0; i < str.length(); i++)
        {
 
            // Calculating max_element at each
            // iteration.
            max_element = Math.max(max_element,
                                       arr[i]);
 
            // if we can not swap the i-th
            // element.
            if (str.charAt(i) == '0') {
 
                // if it is impossible to swap
                // the max_element then we can
                // not sort the array.
                if (max_element > i + 1)
                    return "No";
            }
        }
 
        // Otherwise, we can sort the array.
        return "Yes";
 
    }
 
    // Driven Program
    public static void main(String[] args)
    {
        int arr[] = { 1, 2, 5, 3, 4, 6 };
        int n = arr.length;
        String str = "01110";
        System.out.println(
             possibleToSort(arr, n, str));
    }
}
 
// This code is contributed by Prasad Kshirsagar

Python 3

# Python 3 program to Check if it
# is possible to sort the
# array in ascending order.
 
# Function to check if it is
# possible to sort the array
def possibleToSort(arr, n, str):
 
    max_element = -1
    for i in range(len(str)) :
 
        # Calculating max_element
        # at each iteration.
        max_element = max(max_element, arr[i])
 
        # if we can not swap the i-th element.
        if (str[i] == '0') :
             
            # if it is impossible to swap the
            # max_element then we can not
            # sort the array.
            if (max_element > i + 1):
                return "No"
 
    # Otherwise, we can sort the array.
    return "Yes"
 
# Driver Code
if __name__ == "__main__":
     
    arr = [ 1, 2, 5, 3, 4, 6 ]
    n = len(arr)
    str = "01110"
    print(possibleToSort(arr, n, str))
 
# This code is contributed
# by ChitraNayal

C#

// C# program to Check if it
// is possible to sort the
// array in ascending order
using System;
class GFG {
     
// Function to check if it
// is possible to sort the array
static string possibleToSort(int []arr,
                             int n,
                             string str)
{
    int max_element = -1;
    for (int i = 0; i < str.Length; i++)
    {
 
        // Calculating max_element
        // at each iteration.
        max_element = Math.Max(max_element,
                                   arr[i]);
 
        // if we can not swap
        // the i-th element.
        if (str[i] == '0')
        {
 
            // if it is impossible to swap the
            // max_element then we can not
            // sort the array.
            if (max_element > i + 1)
                return "No";
        }
    }
 
    // Otherwise, we can
    // sort the array.
    return "Yes";
}
 
    // Driver Code
    static public void Main ()
    {
        int []arr = {1, 2, 5, 3, 4, 6};
        int n = arr.Length;
        string str = "01110";
        Console.WriteLine(possibleToSort(arr, n, str));
    }
}
 
// This code is contributed by anuj_67.

PHP

 $i + 1)
                return "No";
        }
    }
 
    // Otherwise, we can sort the array.
    return "Yes";
}
 
// Driver Code
$arr = array(1, 2, 5, 3, 4, 6);
$n = sizeof($arr);
$str = "01110";
echo possibleToSort($arr, $n, $str);
 
// This code is contributed
// by Akanksha Rai
?>

Javascript

输出：

Yes