https://practice.geeksforgeeks.org/problems/longest-common-substring1452/1
Given two strings. The task is to find the length of the longest common substring.
Example 1:
Input: S1 = "ABCDGH", S2 = "ACDGHR" Output: 4 Explanation: The longest common substring is "CDGH" which has length 4. Example 2:
Input: S1 = "ABC", S2 "ACB" Output: 1 Explanation: The longest common substrings are "A", "B", "C" all having length 1.
Your Task: You don't need to read input or print anything. Your task is to complete the function longestCommonSubstr() which takes the string S1, string S2 and their length n and m as inputs and returns the length of the longest common substring in S1 and S2.
Expected Time Complexity: O(nm). Expected Auxiliary Space: O(nm).
Constraints: 1<=n, m<=1000