给定两个算术序列中最不常见的元素
给定四个正数 A、B、C、D ,使得 A 和 B 分别是第一算术序列的第一项和公共差,而 C 和 D 分别表示第二算术序列的相同,如下所示:
第一算术序列: A,A + B,A + 2B,A + 3B,…。 第二等差数列: C,C + D,C + 2D,C + 3D,…。
任务是从上面的 AP 序列中找到最不常见的元素。如果没有,则打印 -1 。
示例:
输入: A = 2,B = 20,C = 19,D = 9 输出: 82 解释: 序列 1: {2,2 + 20,2 + 2(20),2 + 3(20),2+4(20)……..} = {2,22,42,62, 82 ,…..} 序列 2: {19,19 + 9,19 + 2(9),19 + 3(9),19 + 4(9),19 + 5(9),19 + 6(9),19 + 7(9) …..} = {19,28,37,46,55,64,73, 82 ,…..} 因此,82 是最小的公共元素。
输入: A = 2,B = 18,C = 19,D = 9 输出: -1
进场:
由于给定的两个序列的任意项都可以表示为 A + x*B 和 C + y*D ,因此,为了解决这个问题,我们需要找到两项相等的 x 和 y 的最小值。 按照以下步骤解决问题:
- 为了找到在两个 AP 序列中共同的最小值,想法是找到满足以下等式的 x 和 y 的最小整数值:
A + xB = C + yD
= >以上方程可以重新排列为 x * B = C–A+y * D =>以上方程可以进一步重新排列为 x =(C–A+y * D)/B
- 检查是否存在(C–A+y * D)% B为 0 的整数值 y 。如果存在,那么最小的数字是 (C + y*D) 。
- 检查 (C + y*D) 是否为答案,其中 y 会在一个范围内 (0,B) 因为从 i = B,B+1, …。剩余值将被重复。
- 如果以上步骤没有得到这样的数字,则打印 -1 。
下面是上述方法的实现:
C++
// C++ program to implement
// the above approach
#include <bits/stdc++.h>
using namespace std;
// Function to find the smallest element
// common in both the subsequences
long smallestCommon(long a, long b,
long c, long d)
{
// If a is equal to c
if (a == c)
return a;
// If a exceeds c
if (a > c) {
swap(a, c);
swap(b, d);
}
long first_term_diff = (c - a);
long possible_y;
// Check for the satisfying
// equation
for (possible_y = 0; possible_y < b; possible_y++) {
// Least value of possible_y
// satisfying the given equation
// will yield true in the below if
// and break the loop
if ((first_term_diff % b
+ possible_y * d)
% b
== 0) {
break;
}
}
// If the value of possible_y
// satisfying the given equation
// lies in range [0, b]
if (possible_y != b) {
return c + possible_y * d;
}
// If no value of possible_y
// satisfies the given equation
return -1;
}
// Driver Code
int main()
{
long A = 2, B = 20, C = 19, D = 9;
cout << smallestCommon(A, B, C, D);
return 0;
}
Java 语言(一种计算机语言,尤用于创建网站)
// Java program to implement
// the above approach
import java.util.*;
class GFG{
// Function to find the smallest element
// common in both the subsequences
static int smallestCommon(int a, int b,
int c, int d)
{
// If a is equal to c
if (a == c)
return a;
// If a exceeds c
if (a > c)
{
swap(a, c);
swap(b, d);
}
int first_term_diff = (c - a);
int possible_y;
// Check for the satisfying
// equation
for (possible_y = 0;
possible_y < b; possible_y++)
{
// Least value of possible_y
// satisfying the given equation
// will yield true in the below if
// and break the loop
if ((first_term_diff % b +
possible_y * d) % b == 0)
{
break;
}
}
// If the value of possible_y
// satisfying the given equation
// lies in range [0, b]
if (possible_y != b)
{
return c + possible_y * d;
}
// If no value of possible_y
// satisfies the given equation
return -1;
}
static void swap(int x, int y)
{
int temp = x;
x = y;
y = temp;
}
// Driver Code
public static void main(String[] args)
{
int A = 2, B = 20, C = 19, D = 9;
System.out.print(smallestCommon(A, B, C, D));
}
}
// This code is contributed by PrinciRaj1992
Python 3
# Python3 program to implement
# the above approach
# Function to find the smallest element
# common in both the subsequences
def smallestCommon(a, b, c, d):
# If a is equal to c
if (a == c):
return a;
# If a exceeds c
if (a > c):
swap(a, c);
swap(b, d);
first_term_diff = (c - a);
possible_y = 0;
# Check for the satisfying
# equation
for possible_y in range(b):
# Least value of possible_y
# satisfying the given equation
# will yield True in the below if
# and break the loop
if ((first_term_diff % b +
possible_y * d) % b == 0):
break;
# If the value of possible_y
# satisfying the given equation
# lies in range [0, b]
if (possible_y != b):
return c + possible_y * d;
# If no value of possible_y
# satisfies the given equation
return -1;
def swap(x, y):
temp = x;
x = y;
y = temp;
# Driver Code
if __name__ == '__main__':
A = 2; B = 20; C = 19; D = 9;
print(smallestCommon(A, B, C, D));
# This code is contributed by Rajput-Ji
C
// C# program to implement
// the above approach
using System;
class GFG{
// Function to find the smallest element
// common in both the subsequences
static int smallestCommon(int a, int b,
int c, int d)
{
// If a is equal to c
if (a == c)
return a;
// If a exceeds c
if (a > c)
{
swap(a, c);
swap(b, d);
}
int first_term_diff = (c - a);
int possible_y;
// Check for the satisfying
// equation
for (possible_y = 0;
possible_y < b; possible_y++)
{
// Least value of possible_y
// satisfying the given equation
// will yield true in the below if
// and break the loop
if ((first_term_diff % b +
possible_y * d) % b == 0)
{
break;
}
}
// If the value of possible_y
// satisfying the given equation
// lies in range [0, b]
if (possible_y != b)
{
return c + possible_y * d;
}
// If no value of possible_y
// satisfies the given equation
return -1;
}
static void swap(int x, int y)
{
int temp = x;
x = y;
y = temp;
}
// Driver Code
public static void Main(String[] args)
{
int A = 2, B = 20, C = 19, D = 9;
Console.Write(smallestCommon(A, B, C, D));
}
}
// This code is contributed by Rajput-Ji
java 描述语言
<script>
// JavaScript program for the
// above approach
// Function to find the smallest element
// common in both the subsequences
function smallestCommon(a, b, c, d)
{
// If a is equal to c
if (a == c)
return a;
// If a exceeds c
if (a > c)
{
swap(a, c);
swap(b, d);
}
let first_term_diff = (c - a);
let possible_y;
// Check for the satisfying
// equation
for (possible_y = 0;
possible_y < b; possible_y++)
{
// Least value of possible_y
// satisfying the given equation
// will yield true in the below if
// and break the loop
if ((first_term_diff % b +
possible_y * d) % b == 0)
{
break;
}
}
// If the value of possible_y
// satisfying the given equation
// lies in range [0, b]
if (possible_y != b)
{
return c + possible_y * d;
}
// If no value of possible_y
// satisfies the given equation
return -1;
}
function swap(x, y)
{
let temp = x;
x = y;
y = temp;
}
// Driver Code
let A = 2, B = 20, C = 19, D = 9;
document.write(smallestCommon(A, B, C, D));
</script>
Output:
82
时间复杂度: O(B) 辅助空间: O(1)
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