/* ~~~~~UNBEATABLE CHALLENGE~~~~~ WORD PROBLEM :: # 04 Given 2 space separated non-negative numbers representing original number and remove k digits from the number so that the new number is the smallest possible. Input: 1432219 3 Output: 1219 Explanation: Remove the three digits 4, 3, and 2 to form the new number 1219 which is the smallest. Input: 10200 1 Output: 200 Explanation: Remove the leading 1 and the number is 200. Note that the output must not contain leading zeroes. Input: 10 2 Output: 0 Explanation: Remove all the digits from the number and it is left with nothing which is 0. CONSTRAINT : Input must be included in the output The given num does not contain any leading zero. Mandatory : User Input Link your answers in comments No one has completed it yet Ref : https://leetcode.com/problems/remove-k-digits/description/ For more challenges 👇👇👇 https://code.sololearn.com/WudPqFy464fn/?ref=app For any queries, Please concern me""" */ #include using namespace std; using P = pair; auto remove_k_digits(P skpair) { auto&[nstr, k] = skpair; if (nstr.size() <= k) return "0"s; string res{""}; for(size_t i{0}, sz{nstr.size()}; i < sz; ++i) { if(k && !res.empty() && res.back() > nstr[i]) { res.pop_back(); --k; --i; } else if(sz - i <= k) --k; else if(!(res.empty() && nstr[i] =='0')) res += nstr[i]; } return res.empty() ? "0" : res; } int main() { P uinp{"4325043", 3}; cin >> uinp.first >> ws >> uinp.second; P plist[] {{uinp}, {"10200", 1}, {"10", 2}, {"1975263480", 9}, {"1432219", 3}}; for(auto const& p : plist) { cout << '[' << p.first << ',' << p.second << "] ==> " << remove_k_digits(p) << "\n"; } }

[Challenge] remove_k_digits.cpp