给定两个长度为N 的二进制字符串A和B ,任务是找到二进制字符串,其到字符串A和B的汉明距离是A和B的汉明距离的一半。
例子:
Input: A = “1001010”, B = “0101010”
Output: 0001010
Explanation:
The hamming distance of the string A and B is 2.
The hamming distance of the output string to A is 1.
The hamming distance of the output string to B is 1.
Input: A = “1001010”, B = “1101010”
Output: Not Possible
Explanation:
There exist no string which satisfy our condition.
朴素的方法:朴素的方法是生成长度为N 的所有可能的二进制字符串,并计算每个字符串与A和B的汉明距离。如果生成的字符串与给定字符串A和B之间的汉明距离是A和B之间的汉明距离的一半,则生成的字符串是结果字符串。否则不存在这样的字符串。
时间复杂度: O(2 N )
有效的方法:
- 找到两个给定字符串A和B之间的汉明距离(比如 a )。如果是奇数那么我们不能产生另一个字符串与汉明距离(A / 2)与字符串甲乙。
- 如果是偶数,则选择第一个(A / 2)从字符串A字符,这不等于字符串B和下一个从字符串B(A / 2)字符不等于字符串A,使得到的字符串。
- 将字符串A和B 中的相等字符附加到结果字符串。
下面是上述方法的实现:
C++
// C++ implementation of the above
// approach
#include
using namespace std;
// Function to find the required
// string
void findString(string A, string B)
{
int dist = 0;
// Find the hamming distance
// between A and B
for (int i = 0; A[i]; i++) {
if (A[i] != B[i]) {
dist++;
}
}
// If distance is odd, then
// resultant string is not
// possible
if (dist & 1) {
cout << "Not Possible"
<< endl;
}
// Make the resultant string
else {
// To store the final
// string
string res = "";
int K = dist / 2;
// Pick k characters from
// each string
for (int i = 0; A[i]; i++) {
// Pick K characters
// from string B
if (A[i] != B[i] && K > 0) {
res.push_back(B[i]);
K--;
}
// Pick K characters
// from string A
else if (A[i] != B[i]) {
res.push_back(A[i]);
}
// Append the res characters
// from string to the
// resultant string
else {
res.push_back(A[i]);
}
}
// Print the resultant
// string
cout << res << endl;
}
}
// Driver's Code
int main()
{
string A = "1001010";
string B = "0101010";
// Function to find the resultant
// string
findString(A, B);
return 0;
}
Java
// Java implementation of the above
// approach
class GFG
{
// Function to find the required
// string
static void findString(String A, String B)
{
int dist = 0;
// Find the hamming distance
// between A and B
for (int i = 0; i < A.length(); i++)
{
if(A.charAt(i) != B.charAt(i))
dist++;
}
// If distance is odd, then
// resultant string is not
// possible
if((dist & 1) == 1)
{
System.out.println("Not Possible");
}
// Make the resultant string
else
{
// To store the final
// string
String res = "";
int K = (int)dist / 2;
// Pick k characters from
// each string
for (int i = 0; i < A.length(); i++) {
// Pick K characters
// from string B
if (A.charAt(i) != B.charAt(i) && K > 0) {
res += B.charAt(i);
K--;
}
// Pick K characters
// from string A
else if (A.charAt(i) != B.charAt(i)) {
res += A.charAt(i);
}
// Append the res characters
// from string to the
// resultant string
else {
res += A.charAt(i);
}
}
// Print the resultant
// string
System.out.println(res) ;
}
}
// Driver's Code
public static void main (String[] args)
{
String A = "1001010";
String B = "0101010";
// Function to find the resultant
// string
findString(A, B);
}
}
// This code is contributed by Yash_R
Python3
# Python3 implementation of the above
# approach
# Function to find the required
# string
def findString(A, B) :
dist = 0;
# Find the hamming distance
# between A and B
for i in range(len(A)) :
if (A[i] != B[i]) :
dist += 1;
# If distance is odd, then
# resultant string is not
# possible
if (dist & 1) :
print("Not Possible");
# Make the resultant string
else :
# To store the final
# string
res = "";
K = dist // 2;
# Pick k characters from
# each string
for i in range(len(A)) :
# Pick K characters
# from string B
if (A[i] != B[i] and K > 0) :
res += B[i];
K -= 1;
# Pick K characters
# from string A
elif (A[i] != B[i]) :
res += A[i];
# Append the res characters
# from string to the
# resultant string
else :
res += A[i];
# Print the resultant
# string
print(res);
# Driver's Code
if __name__ == "__main__" :
A = "1001010";
B = "0101010";
# Function to find the resultant
# string
findString(A, B);
# This code is contributed by Yash_R
C#
// C# implementation of the above approach
using System;
class GFG
{
// Function to find the required
// string
static void findString(string A, string B)
{
int dist = 0;
// Find the hamming distance
// between A and B
for (int i = 0; i < A.Length; i++)
{
if(A[i] != B[i])
dist++;
}
// If distance is odd, then
// resultant string is not
// possible
if((dist & 1) == 1)
{
Console.WriteLine("Not Possible");
}
// Make the resultant string
else
{
// To store the final
// string
string res = "";
int K = (int)dist / 2;
// Pick k characters from
// each string
for (int i = 0; i < A.Length; i++) {
// Pick K characters
// from string B
if (A[i] != B[i] && K > 0) {
res += B[i];
K--;
}
// Pick K characters
// from string A
else if (A[i] != B[i]) {
res += A[i];
}
// Append the res characters
// from string to the
// resultant string
else {
res += A[i];
}
}
// Print the resultant
// string
Console.WriteLine(res) ;
}
}
// Driver's Code
public static void Main (string[] args)
{
string A = "1001010";
string B = "0101010";
// Function to find the resultant
// string
findString(A, B);
}
}
// This code is contributed by Yash_R
输出:
0001010
时间复杂度: O(N),其中 N 是字符串的长度。
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