给定一个大小为N的数组arr[]和一个字符串S ，任务是通过从S中存在的十六进制表示中删除所有字符，然后将等效的十进制元素替换回数组来修改给定数组。
例子：
Input: arr[] = {74, 91, 31, 122}, S = “1AB”
Output: {4, 5, 15, 7}
Explanation:
74 -> (4A)16 -> (4)16 -> 4
91 -> (5B)16 -> (5)16 -> 5
31 -> (1F)16 -> (F)16 -> 15
122 -> (7A)16 -> (7)16 -> 7
Input: arr[] = {1450, 1716, 284, 843}, S = “ABFE3”
Output: {5, 100, 284, 4}
处理方法：按照以下步骤解决问题：
- 遍历数组arr[]：
- 将每个数组元素转换为其等效的十六进制值。
- 从字符串S 中存在的十六进制数中删除字符。
- 将修改后的十六进制数转换回其十进制表示。
- 用它替换数组元素。
- 打印修改后的数组。
下面是上述方法的实现：
C++
// C++ program for the above approach
#include
using namespace std;
// Function to convert a decimal number
// to its equivalent hexadecimal number
string decHex(int n)
{
char alpha[] = { 'A', 'B', 'C', 'D', 'E', 'F' };
string ans;
while (n > 0) {
if (n % 16 < 10) {
ans += to_string(n % 16);
}
else {
ans += alpha[n % 16 - 10];
}
n /= 16;
}
reverse(ans.begin(), ans.end());
return ans;
}
// Function to convert hexadecimal number
// to its equavalent decimal number
int hexDec(string convertedHex)
{
// Stores characters with their
// respective hexadecimal values
char mp[] = { 10, 11, 12, 13, 14, 15 };
// Stores answer
int ans = 0;
int pos = 0;
// Traverse the string
reverse(convertedHex.begin(), convertedHex.end());
for (char ch : convertedHex) {
// If digit
if (isdigit(ch)) {
ans += ((int)pow(16, pos)) * (ch - '0');
}
// If character
else {
ans += ((int)pow(16, pos)) * mp[ch - 'A'];
}
pos += 1;
}
// Return the answer
return ans;
}
// Function to move all the
// alphabets to front
string removeChars(string hexaVal, string S)
{
set setk;
for (char ch : S) {
setk.insert(ch);
}
string ans = "";
for (char ch : hexaVal) {
if (setk.find(ch) != setk.end()) {
continue;
}
ans += ch;
}
return ans;
}
// Function to modify each array
// element by removing characters
// from their hexadecimal representation
// which are present in a given string
void convertArr(int arr[], int N, string S)
{
// Traverse the array
for (int i = 0; i < N; i++) {
// Stores hexadecimal value
string hexaVal = decHex(arr[i]);
// Remove the characters from hexadecimal
// representation present in string S
string convertedHex = removeChars(hexaVal, S);
// Stores decimal value
int decVal = hexDec(convertedHex);
// Replace array element
arr[i] = decVal;
}
// Print the modified array
for (int i = 0; i < N; i++) {
cout << arr[i] << " ";
}
}
// Driven Program
int main()
{
// Given array
int arr[] = { 74, 91, 31, 122 };
int N = sizeof(arr) / sizeof(arr[0]);
// Given string
string S = "1AB";
// Function call to modify
// array by given operations
convertArr(arr, N, S);
return 0;
}
// This code is contributed by Kingash. Java
// java program for the above approach
import java.io.*;
import java.lang.*;
import java.util.*;
class GFG {
// Function to convert a decimal number
// to its equivalent hexadecimal number
static String decHex(int n)
{
char alpha[] = { 'A', 'B', 'C', 'D', 'E', 'F' };
StringBuilder ans = new StringBuilder("");
while (n > 0) {
if (n % 16 < 10) {
ans.append(Integer.toString(n % 16));
}
else {
ans.append(alpha[n % 16 - 10]);
}
n /= 16;
}
ans = ans.reverse();
return ans.toString();
}
// Function to convert hexadecimal number
// to its equavalent decimal number
static int hexDec(String convertedHex)
{
// Stores characters with their
// respective hexadecimal values
char mp[] = { 10, 11, 12, 13, 14, 15 };
// Stores answer
int ans = 0;
int pos = 0;
// Traverse the string
StringBuilder s = new StringBuilder(convertedHex);
convertedHex = s.reverse().toString();
for (char ch : convertedHex.toCharArray()) {
// If digit
if (Character.isDigit(ch)) {
ans += ((int)Math.pow(16, pos))
* (ch - '0');
}
// If character
else {
ans += ((int)Math.pow(16, pos))
* mp[ch - 'A'];
}
pos += 1;
}
// Return the answer
return ans;
}
// Function to move all the
// alphabets to front
static String removeChars(String hexaVal, String S)
{
HashSet setk = new HashSet<>();
for (char ch : S.toCharArray()) {
setk.add(ch);
}
String ans = "";
for (char ch : hexaVal.toCharArray()) {
if (setk.contains(ch)) {
continue;
}
ans += ch;
}
return ans;
}
// Function to modify each array
// element by removing characters
// from their hexadecimal representation
// which are present in a given string
static void convertArr(int arr[], String S)
{
// Traverse the array
for (int i = 0; i < arr.length; i++) {
// Stores hexadecimal value
String hexaVal = decHex(arr[i]);
// Remove the characters from hexadecimal
// representation present in string S
String convertedHex = removeChars(hexaVal, S);
// Stores decimal value
int decVal = hexDec(convertedHex);
// Replace array element
arr[i] = decVal;
}
// Print the modified array
for (int val : arr) {
System.out.print(val + " ");
}
}
// Driver Code
public static void main(String[] args)
{
// Given array
int arr[] = { 74, 91, 31, 122 };
// Given string
String S = "1AB";
// Function call to modify
// array by given operations
convertArr(arr, S);
}
}
// This code is contributed by Kingash. Python3
# Python3 program for the above approach
# Function to convert a decimal number
# to its equivalent hexadecimal number
def decHex(n):
alpha = ['A', 'B', 'C', 'D', 'E', 'F']
ans = ''
while n:
if n % 16 < 10:
ans += str(n % 16)
else:
ans += alpha[n % 16 - 10]
n //= 16
ans = ans[::-1]
return ans
# Function to convert hexadecimal number
# to its equavalent decimal number
def hexDec(convertedHex):
# Stores characters with their
# respective hexadecimal values
mp = {"A": 10, "B": 11, "C": 12,
"D": 13, "E": 14, "F": 15}
# Stores answer
ans = 0
pos = 0
# Traverse the string
for i in convertedHex[::-1]:
# If digit
if i.isdigit():
ans += (16**pos)*int(i)
# If character
else:
ans += (16**pos)*mp[i]
pos += 1
# Return the answer
return ans
# Function to move all the
# alphabets to front
def removeChars(hexaVal, S):
setk = set()
for i in S:
setk.add(i)
ans = ''
for i in hexaVal:
if i in setk:
continue
ans += i
return ans
# Function to modify each array
# element by removing characters
# from their hexadecimal representation
# which are present in a given string
def convertArr(arr, S):
# Traverse the array
for i in range(len(arr)):
# Stores hexadecimal value
hexaVal = decHex(arr[i])
# Remove the characters from hexadecimal
# representation present in string S
convertedHex = removeChars(hexaVal, S)
# Stores decimal value
decVal = hexDec(convertedHex)
# Replace array element
arr[i] = decVal
# Print the modified array
print(arr)
# Driver Code
# Given array
arr = [74, 91, 31, 122]
# Given string
S = "1AB"
# Function call to modify
# array by given operations
convertArr(arr, S)输出：
[4, 5, 15, 7]时间复杂度： O(N * |S|)
辅助空间： O(|S|)
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