Educational Codeforces Round 120 Editorial [problem:1622A] Idea: [user:BledDest,2021-12-28] <spoiler summary="Tutorial"> [tutorial:1622A] </spoiler> <spoiler summary="Solution (Neon)"> ~~~~~ #include <bits/stdc++.h> using namespace std; int main() { int t; cin >> t; while (t--) { vector<int> l(3); for (int i = 0; i < 3; ++i) cin >> l[i]; bool ok = false; for (int i = 0; i < 3; ++i) ok |= l[i] == l[(i + 1) % 3] + l[(i + 2) % 3]; for (int i = 0; i < 3; ++i) if (l[i] % 2 == 0) ok |= l[(i + 1) % 3] == l[(i + 2) % 3]; cout << (ok ? "YES\n" : "NO\n"); } } ~~~~~ </spoiler> [problem:1622B] Idea: [user:adedalic,2021-12-28] <spoiler summary="Tutorial"> [tutorial:1622B] </spoiler> <spoiler summary="Solution (awoo)"> ~~~~~ for _ in range(int(input())): n = int(input()) p = [int(x) for x in input().split()] s = input() l = sorted([[s[i], p[i], i] for i in range(n)]) q = [-1 for i in range(n)] for i in range(n): q[l[i][2...

Full text and comments »

A hack for Problem C: "Set or Decrease" (Educational Round #120) [problem:1622C] ================== A few others and I had solutions for this problem that passed the system tests but had a bad time complexity of `O(aᵢ * t)`. The problem has `aᵢ <= 10^9` and `t <= 10^4` so `aᵢ * t` can be up to `10^13`, which could take over an hour for the code to run, and would obviously give the "Time Limit Exceeded" verdict. For any step, if you choose **set**, it is optimal to set the greatest element (that hasn't been set yet) equal to the smallest element, because this decreases the sum the most. If you choose **decrease**, it is optimal to decrease the smallest element. It's optimal to do all the **decrease**s before all the **set**s, because this way the largest elements can be set to an even lower number, compared to if any **set** step is done before a **decrease** step. My initial approach to this problem (with the wrong time complexity) was to simulate the steps one by one, on each step choosing greedily whether to **set** or **decrease**...

Full text and comments »

Unable to find the mistake I am getting WA in Test case 2, particularly : wrong answer 35th numbers differ &mdash; expected: '1', found: '0'. I am unable to find the error in my code for this problem: [problem:1622C] My submission:[submission:193454039]. The logic I used: 

Full text and comments »

Almost same Submissions yielding different results. Hi Codeforces, I was trying to solve yesterday's [problem:1622C] and made [this submission](https://codeforces.me/contest/1622/submission/140860168) which failed at test case 3 but after a bit of cleaning up In code I made [this submission](https://codeforces.me/problemset/submission/1622/140860992) and this was accepted. Can anyone please help me and explain why this happened?

Full text and comments »

Find the minimum number of operations/steps - [problem:1367F1] - [problem:2114F] - [problem:1556A] - [problem:1728C] - [problem:1622C] - [problem:662C] - [problem:727A]

Full text and comments »