# Minimize length of a string by removing pairs of consecutive increasing or decreasing digits

Minimize length of a string by removing pairs of consecutive increasing or decreasing digitsGiven a numeric string S consisting of N digits, the task is to find the minimum length of the string that can be formed by repeatedly removing pairs of adjacent consecutive characters arranged in either increasing or decreasing order.Examples:Input: S = “12213”Output: 1Explanation:The minimum length of the string S that can be obtained by removing elements in following way:Remove substring {S[0], S[1]}. The string S modifies to “213”Remove substring {S[0], S[1]}. The string S modifies to “3”Therefore, the length of the string S is 1, which is the minimum possible length.Input: S = “1350”Output: 4Approach: The given problem can be solved using the Stack Data Structure. Follow the steps below to solve the problem:Below is the implementation of this approach:C++#include using namespace std;int minLength(string S){ stack st; for (auto ch : S) { if (st.empty()) st.push(ch); else { char top = st.top(); if (abs(ch – top) == 1) st.pop(); else { st.push(ch); } } } return st.size();}int main(){ string S = “12213”; cout