Ad-hoc Training
Difficulty range [1, 10], where ≤ 5 is easy, 6 requires thinking for ≤ 30min, 7 is barely solvable (1h). 8 means it's unsolvable but seems not difficult. 9 is currently unsolvable but can be naturally derived from the solution. 10 is extremely difficult to understand even the solution.
Thinking time should be around [40, 80] min, not ≤ 30 min.
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Posted on Sat, 20 Jun 2026 17:01:21 +0000 by philvia
Solutions to AGC016 Programming Contest Problems
A - Shrinking
Given a string s, determine the minimum number of operasions required to make all characters identical. Each operation reduces the string length by one by selecting characters from adjacent positions.
#include <bits/stdc++.h>
using namespace std;
int main() {
string input;
cin >> input;
int length = input. ...
Posted on Fri, 19 Jun 2026 17:54:39 +0000 by decodv
Algorithmic Review and Competition Strategies for NOIP
Contest preparation requires a structured approach to covering fundamental algorithms and optimizing problem-solving strategies. The following outlines core technical topics and execution practices essential for competitive programming.
Core Algorithms and Data Structures
Simulation and Mathematics
High-precision arithmetic is critical for p ...
Posted on Mon, 15 Jun 2026 17:54:23 +0000 by press711
Core Algorithmic Techniques in Java for Competitive Programming
Sorting, searching, dynamic programing, and graph algorithms form the backbone of competitive programming. This article presents a curated list of such patterns, each accompanied by a concise Java implementation. The examples draw inspiration from the ACwing problem set, covering topics from basic sorting to advanced combinatorial mathematics.
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Posted on Mon, 15 Jun 2026 17:07:00 +0000 by zhaohongli
Solving Problems ABC 269 (A-G)
A: Basic Arithmetic and Output
Given integers a, b, c, d, compute (a + b) * (c - d) and output the result followed by the string "Takahashi".
int a = input(), b = input(), c = input(), d = input();
cout << (a + b) * (c - d) << endl;
cout << "Takahashi" << endl;
Time complexity: O(1)
B: Finding Corne ...
Posted on Wed, 10 Jun 2026 16:36:46 +0000 by Elephant
Problem Solving Approaches for AtCoder Beginner Contest 045
Problem A: Trapezoid Area
Given the upper base $a$, lower base $b$, and height $h$ of a trapezoid, the area is calculated using the formula:
$$\text{Area} = \frac{(a + b) \times h}{2}$$
Problem B: Card Game for Three
Three players, A, B, and C, each start with a string of cards. Starting with player A, they draw cards in a sequence. If a player ...
Posted on Tue, 09 Jun 2026 17:50:46 +0000 by Ben5on
Competitive Programming Code Templates and Common Algorithms
Header File Templates
C++ Template
#include <bits/stdc++.h>
#define fi first
#define endl '\n'
#define se second
#define lowbit(x) ((x)&(-(x)))
#define all(x) begin(x), end(x)
#define lp(i, j, k) for(int i = int(j); i <= int(k); i++)
#define rlp(i, j, k) for(int i = int(j); i >= int(k); i++)
#define IO std::ios::sync_with_std ...
Posted on Mon, 08 Jun 2026 17:51:31 +0000 by atstein
Algorithmic Solutions for String Processing, Greedy Maximization, and Graph Dependencies
Prefix Matching and Keyboard Layout Reconstruction
This problem involves identifying possible next characters based on a given prefix and mapping them to a specific $4 \times 8$ grid layout. The core task is to filter a list of strings that start with a specific sequence and mark the character that immediately follows that sequence.
#include &l ...
Posted on Sun, 07 Jun 2026 16:46:38 +0000 by rednax
Contest Problem Solutions: Factorization, Rays, String Construction, and Tree Partitioning
Factorization into Factorial Divisors
Given integers (n) and (m) where (1 \le m \le n!) and (n \le 20), decompose (m) into a sum of at most (n) divisors of (n!). A solution is guaranteed to exist.
Define a sequence (d_i = \frac{n!}{i!}) for (i) from 1 to (n). By iterating downwards from (i=n) to (1) and greedily subtracting the largest possible ...
Posted on Mon, 01 Jun 2026 17:41:27 +0000 by taldos
Solving Codeforces Division 3 Round: Algorithmic Approaches and Implementations
Problem A: Minimum Steps to Visit All Points Given a array of distinct integers x₁, x₂, ..., xₙ and a starting position s on the number line. You can move left or right by one unit each step. Find the minimum number of steps required to visit all positions in the array, starting from position s. The optimal solution involves visiting the endpoi ...
Posted on Sun, 31 May 2026 23:51:47 +0000 by phant0m