Given two given arrays **A** and **B** of equal length, the task is to find the maximum number of distinct pairs of elements that can be chosen such that the element from A is strictly greater than the element from B.

**Examples:**

Input:

A[]={20, 30, 50} , B[]={25, 60, 40}Output:2Explanation:

(30, 25) and (50, 40) are the two possible pairs.

Input:

A[]={20, 25, 60} , B[]={25, 60, 40}Output:1Explanation:

(60, 25) or (60, 40) can be the required pair.

**Approach:** In order to solve this problem we need to adopt the following approach:

- Sort both the arrays.
- Traverse the entire length of array A and check if the current element in A is greater than the element in B currently pointed at B.
- If so, point to the next element in both the arrays. Otherwise, move to the next element in A and check if it is greater than the element currently pointed at B.
- The number of elements traversed in array B after the entire traversal of array A gives the required answer.

Illustration:

Let us consider the two following arrays:

A[] = { 30, 28, 45, 22 } , B[] = { 35, 25, 22, 48 }

After sorting, the arrays appear to be

A[] = { 22, 28, 30, 45 } , B[] = { 22, 25, 35, 48}After the first iteration, since A[0] is not greater than B[0], we move to A[1].

After the second iteration, we move to B[1] as A[1] is greater than B[0].

After the third iteration, we move to B[2] as A[2] is greater than B[1].

Similarly, A[3] is greater than B[2] and we move to B[3].

Hence the number of elements traversed in B,i.e. 3 is the final answer.

The possible pairs are (28,22), (30,25) are (45, 35).

Below is the implementation of the above approach:

`// C++ Program to count number of distinct ` `// pairs possible from the two arrays ` `// such that element selected from one array is ` `// always greater than the one selected from ` `// the other array ` ` ` `#include <bits/stdc++.h> ` `using` `namespace` `std; `
` ` `// Function to return the count ` `// of pairs ` `int` `countPairs(vector<` `int` `> A, `
` ` `vector<` `int` `> B) `
`{ ` ` ` `int` `n = A.size(); `
` ` ` ` `sort(A.begin(),A.end()); `
` ` `sort(B.begin(),B.end()); `
` ` ` ` `int` `ans = 0, i; `
` ` `for` `(` `int` `i = 0; i < n; i++) { `
` ` `if` `(A[i] > B[ans]) { `
` ` `ans++; `
` ` `} `
` ` `} `
` ` ` ` `return` `ans; `
`} ` ` ` `// Driver code ` `int` `main() `
`{ ` ` ` `vector<` `int` `> A = { 30, 28, 45, 22 }; `
` ` `vector<` `int` `> B = { 35, 25, 22, 48 }; `
` ` ` ` `cout << countPairs(A,B); `
` ` ` ` `return` `0; `
`} ` |

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`// Java program to count number of distinct ` `// pairs possible from the two arrays such ` `// that element selected from one array is ` `// always greater than the one selected from ` `// the other array ` `import` `java.util.*; `
` ` `class` `GFG{ `
` ` `// Function to return the count ` `// of pairs ` `static` `int` `countPairs(` `int` `[] A, `
` ` `int` `[] B) `
`{ ` ` ` `int` `n = A.length; `
` ` `int` `ans = ` `0` `; `
` ` ` ` `Arrays.sort(A); `
` ` `Arrays.sort(B); `
` ` ` ` `for` `(` `int` `i = ` `0` `; i < n; i++) `
` ` `{ `
` ` `if` `(A[i] > B[ans]) `
` ` `{ `
` ` `ans++; `
` ` `} `
` ` `} `
` ` `return` `ans; `
`} ` ` ` `// Driver code ` `public` `static` `void` `main(String[] args) `
`{ ` ` ` `int` `[] A = { ` `30` `, ` `28` `, ` `45` `, ` `22` `}; `
` ` `int` `[] B = { ` `35` `, ` `25` `, ` `22` `, ` `48` `}; `
` ` ` ` `System.out.print(countPairs(A, B)); `
`} ` `} ` ` ` `// This code is contributed by sapnasingh4991 ` |

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`# Python3 program to count number of distinct ` `# pairs possible from the two arrays ` `# such that element selected from one array is ` `# always greater than the one selected from ` `# the other array ` ` ` `# Function to return the count ` `# of pairs ` `def` `countPairs(A, B): `
` ` ` ` `n ` `=` `len` `(A) `
` ` ` ` `A.sort() `
` ` `B.sort() `
` ` ` ` `ans ` `=` `0`
` ` `for` `i ` `in` `range` `(n): `
` ` `if` `(A[i] > B[ans]): `
` ` `ans ` `+` `=` `1`
` ` ` ` `return` `ans `
` ` `# Driver code ` `if` `__name__ ` `=` `=` `'__main__'` `: `
` ` `A ` `=` `[` `30` `, ` `28` `, ` `45` `, ` `22` `] `
` ` `B ` `=` `[` `35` `, ` `25` `, ` `22` `, ` `48` `] `
` ` ` ` `print` `(countPairs(A, B)) `
` ` `# This code is contributed by Shivam Singh ` |

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`// C# program to count number of distinct ` `// pairs possible from the two arrays such ` `// that element selected from one array is ` `// always greater than the one selected from ` `// the other array ` `using` `System; `
`class` `GFG{ `
` ` `// Function to return the count ` `// of pairs ` `static` `int` `countPairs(` `int` `[] A, `
` ` `int` `[] B) `
`{ ` ` ` `int` `n = A.Length; `
` ` `int` `ans = 0; `
` ` ` ` `Array.Sort(A); `
` ` `Array.Sort(B); `
` ` ` ` `for` `(` `int` `i = 0; i < n; i++) `
` ` `{ `
` ` `if` `(A[i] > B[ans]) `
` ` `{ `
` ` `ans++; `
` ` `} `
` ` `} `
` ` `return` `ans; `
`} ` ` ` `// Driver code ` `public` `static` `void` `Main() `
`{ ` ` ` `int` `[]A = { 30, 28, 45, 22 }; `
` ` `int` `[]B = { 35, 25, 22, 48 }; `
` ` ` ` `Console.Write(countPairs(A, B)); `
`} ` `} ` ` ` `// This code is contributed by Code_Mech ` |

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**Output:**

3

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