检查一个数组是否是另一个数组的子数组
给定两个数组 A[] 和 B[]，由
和
整数。任务是检查数组 B[] 是否是数组 A[] 的子数组。
例子：
Input : A[] = {2, 3, 0, 5, 1, 1, 2}, B[] = {3, 0, 5, 1}
Output : Yes
Input : A[] = {1, 2, 3, 4, 5}, B[] = {2, 5, 6}
Output : No
资料来源：签证面试经验
简单方法：一种简单的方法是运行两个嵌套循环并生成数组 A[] 的所有子数组，然后再使用一个循环检查 A[] 的任何子数组是否等于数组 B[]。
高效方法：一种有效的方法是使用两个指针同时遍历两个数组。保持数组 B[] 的指针不变，如果 A[] 的任何元素与 B[] 的第一个元素匹配，则增加两个数组的指针，否则将 A 的指针设置为前一个起点的下一个元素，并且将 B 的指针重置为 0。如果 B 的所有元素都匹配，则打印 YES，否则打印 NO。
下面是上述方法的实现：
C++
// C++ program to check if an array is
// subarray of another array
#include
using namespace std;
// Function to check if an array is
// subarray of another array
bool isSubArray(int A[], int B[], int n, int m)
{
// Two pointers to traverse the arrays
int i = 0, j = 0;
// Traverse both arrays simultaneously
while (i < n && j < m) {
// If element matches
// increment both pointers
if (A[i] == B[j]) {
i++;
j++;
// If array B is completely
// traversed
if (j == m)
return true;
}
// If not,
// increment i and reset j
else {
i = i - j + 1;
j = 0;
}
}
return false;
}
// Driver Code
int main()
{
int A[] = { 2, 3, 0, 5, 1, 1, 2 };
int n = sizeof(A) / sizeof(int);
int B[] = { 3, 0, 5, 1 };
int m = sizeof(B) / sizeof(int);
if (isSubArray(A, B, n, m))
cout << "YES\n";
else
cout << "NO\n";
return 0;
} Java
// Java program to check if an array is
// subarray of another array
class gfg
{
// Function to check if an array is
// subarray of another array
static boolean isSubArray(int A[], int B[],
int n, int m)
{
// Two pointers to traverse the arrays
int i = 0, j = 0;
// Traverse both arrays simultaneously
while (i < n && j < m)
{
// If element matches
// increment both pointers
if (A[i] == B[j])
{
i++;
j++;
// If array B is completely
// traversed
if (j == m)
return true;
}
// If not,
// increment i and reset j
else
{
i = i - j + 1;
j = 0;
}
}
return false;
}
// Driver Code
public static void main(String arr[])
{
int A[] = { 2, 3, 0, 5, 1, 1, 2 };
int n = A.length;
int B[] = { 3, 0, 5, 1 };
int m = B.length;
if (isSubArray(A, B, n, m))
System.out.println("YES");
else
System.out.println("NO");
}
}
// This code is contributed by gp6Python3
# Python3 program to check if an array is
# subarray of another array
# Function to check if an array is
# subarray of another array
def isSubArray(A, B, n, m):
# Two pointers to traverse the arrays
i = 0; j = 0;
# Traverse both arrays simultaneously
while (i < n and j < m):
# If element matches
# increment both pointers
if (A[i] == B[j]):
i += 1;
j += 1;
# If array B is completely
# traversed
if (j == m):
return True;
# If not,
# increment i and reset j
else:
i = i - j + 1;
j = 0;
return False;
# Driver Code
if __name__ == '__main__':
A = [ 2, 3, 0, 5, 1, 1, 2 ];
n = len(A);
B = [ 3, 0, 5, 1 ];
m = len(B);
if (isSubArray(A, B, n, m)):
print("YES");
else:
print("NO");
# This code is contributed by Rajput-JiC#
// C# program to check if an array is
// subarray of another array
using System;
public class GFG
{
// Function to check if an array is
// subarray of another array
static bool isSubArray(int []A, int []B,
int n, int m)
{
// Two pointers to traverse the arrays
int i = 0, j = 0;
// Traverse both arrays simultaneously
while (i < n && j < m)
{
// If element matches
// increment both pointers
if (A[i] == B[j])
{
i++;
j++;
// If array B is completely
// traversed
if (j == m)
return true;
}
// If not,
// increment i and reset j
else
{
i = i - j + 1;
j = 0;
}
}
return false;
}
// Driver Code
public static void Main(String []arr)
{
int []A = { 2, 3, 0, 5, 1, 1, 2 };
int n = A.Length;
int []B = { 3, 0, 5, 1 };
int m = B.Length;
if (isSubArray(A, B, n, m))
Console.WriteLine("YES");
else
Console.WriteLine("NO");
}
}
// This code is contributed by PrinciRaj1992Javascript
输出：
YES