找到最多换 K 位可以组成的最大数字

原文:https://www . geeksforgeeks . org/find-最多改变 k 位数可以形成的最大数字/

给定代表一个数的字符串 str 和一个整数 K ,任务是找出给定数中最多改变 K 位可以构成的最大数。

示例:

输入: str = "569431 ",K = 3 输出: 999931 将第一、二、四位数字替换为 9。 输入: str = "5687 ",K = 2 输出: 9987

方法:为了得到可能的最大数字,最左边的数字必须替换为 9s。对于从最左边的数字开始的数字的每一个数字,如果它还不是 9,并且 K 大于 0,那么用 9 替换它,并将 K 减 1。当 K 大于 0 时,对每个数字重复这些步骤。最后,打印更新后的号码。

下面是上述方法的实现:

C++

// C++ implementation of the approach
#include <iostream>
using namespace std;

// Function to return the maximum number
// that can be formed by changing
// at most k digits in str
string findMaximumNum(string str, int n, int k)
{

    // For every digit of the number
    for (int i = 0; i < n; i++) {

        // If no more digits can be replaced
        if (k < 1)
            break;

        // If current digit is not already 9
        if (str[i] != '9') {

            // Replace it with 9
            str[i] = '9';

            // One digit has been used
            k--;
        }
    }

    return str;
}

// Driver code
int main()
{
    string str = "569431";
    int n = str.length();
    int k = 3;

    cout << findMaximumNum(str, n, k);

    return 0;
}

Java 语言(一种计算机语言,尤用于创建网站)

// Java implementation of the approach
class GFG
{
    // Function to return the maximum number
    // that can be formed by changing
    // at most k digits in str
    static StringBuilder findMaximumNum(StringBuilder str,
                                             int n, int k)
    {

        // For every digit of the number
        for (int i = 0; i < n; i++)
        {

            // If no more digits can be replaced
            if (k < 1)
                break;

            // If current digit is not already 9
            if (str.charAt(i) != '9')
            {

                // Replace it with 9
                str.setCharAt(i, '9');

                // One digit has been used
                k--;
            }
        }
        return str;
    }

    // Driver code
    public static void main (String [] args)
    {
        StringBuilder str = new StringBuilder("569431");

        int n = str.length();
        int k = 3;

        System.out.println(findMaximumNum(str, n, k));
    }
}

// This code is contributed by ihritik

Python 3

# Python3 implementation of the approach

# Function to return the maximum number
# that can be formed by changing
# at most k digits in str
def findMaximumNum(st, n, k):

    # For every digit of the number
    for i in range(n):

        # If no more digits can be replaced
        if (k < 1):
            break

        # If current digit is not already 9
        if (st[i] != '9'):

            # Replace it with 9
            st = st[0:i] + '9' + st[i + 1:]

            # One digit has been used
            k -= 1

    return st

# Driver code
st = "569431"
n = len(st)
k = 3
print(findMaximumNum(st, n, k))

# This code is contributed by
# divyamohan123

C

// C# implementation of the approach
using System;
using System.Text;

class GFG
{
    // Function to return the maximum number
    // that can be formed by changing
    // at most k digits in str
    static StringBuilder findMaximumNum(StringBuilder str,
                                        int n, int k)
    {

        // For every digit of the number
        for (int i = 0; i < n; i++)
        {

            // If no more digits can be replaced
            if (k < 1)
                break;

            // If current digit is not already 9
            if (str[i] != '9')
            {

                // Replace it with 9
                str[i] = '9';

                // One digit has been used
                k--;
            }
        }
        return str;
    }

    // Driver code
    public static void Main ()
    {
        StringBuilder str = new StringBuilder("569431");

        int n = str.Length;
        int k = 3;

        Console.WriteLine(findMaximumNum(str, n, k));
    }
}

// This code is contributed by ihritik

java 描述语言

<script>
      // JavaScript implementation of the approach
      // Function to return the maximum number
      // that can be formed by changing
      // at most k digits in str
      function findMaximumNum(str, n, k) {
        // For every digit of the number
        for (var i = 0; i < n; i++) {
          // If no more digits can be replaced
          if (k < 1) break;

          // If current digit is not already 9
          if (str[i] !== "9") {
            // Replace it with 9
            str[i] = "9";

            // One digit has been used
            k--;
          }
        }
        return str.join("");
      }

      // Driver code
      var str = "569431";
      var n = str.length;
      var k = 3;

      document.write(findMaximumNum(str.split(""), n, k));
    </script>

Output: 

999931