Given a string, find length of the longest repeating subsequence such that the two subsequence don’t have same string character at same position, i.e., anyithcharacter in the two subsequences shouldn’t have the same index in the original string.

Have you met this question in a real interview?

Yes

Example

str =abc, return0, There is no repeating subsequence

str =aab, return1, The two subsequence area(first) anda(second).
Note thatbcannot be considered as part of subsequence as it would be at same index in both.

str =aabb, return2

class Solution {

public:

/\*\*

 \* @param str a string

 \* @return the length of the longest repeating subsequence

 \*/

int longestRepeatingSubsequence\(string& str\) {

    // Write your code here

    if \(str.empty\(\)\) {

        return 0;

    }

    int n = str.length\(\);

    vector<vector<int>> f\(n + 1, vector<int>\(n + 1, 0\)\);



    for \(int i = 1;  i <= n; ++i\) {

        for \(int j = 1; j <= n; ++j\) {

            if \(str\[i - 1\] == str\[j - 1\] && i != j\) {

                f\[i\]\[j\] = f\[i - 1\]\[j - 1\] + 1;

            } else {

                f\[i\]\[j\] = max\(f\[i\]\[j - 1\], f\[i - 1\]\[j\]\);

            }

        }

    }



    return f\[n\]\[n\];

}

};