Freaks City

Recursive Permutation Generation This approach generates all permutations through recursive swaps. The algorithm fixes each character at the first position and recursively permutes the remaining substring. public class PermutationGenerator { public static void main(String[] args) { String text = "abc"; permute( ...

Dragon Slayer Pathfinding with Binary Enumeration Coordinate scaling converts decimal start/end points to integers for grid processing. Binary enumeration efficiently searches all possible wall removal combinations. #include <iostream> #include <vector> #include <bitset> using namespace std; struct Barrier { int x_start, ...

The task is to generate all possible combinations of r distinct numbers from the set {1, 2, ..., n}. A combination is an unordered selection, meaning {1, 2, 3} is the same as {3, 2, 1}. We need to print each combination on a new line, with numbers sorted in ascending order and each number occupying exactly three characters of space. The combina ...

Problem A: Counting Digit Holes The task requires calculating the total number of closed loops (holes) in a sequence of digits. Digits '0', '6', and '9' contain one loop each, while '8' contains two loops. The solution involves iterating through the string and accumulating the count based on the digit encountered. #include <iostream> #inc ...

This article addresses the problem of finding the coefficient of the $x^n y^m$ term in the expansion of the polynomial $(ax + by)^k$. The solution involves applying the binoimal theorem and calculating combinations modulo 10007. Binomial Theorem Application The binomial theorem states that $(x+y)^k = \sum_{i=0}^{k} \binom{k}{i} x^{k-i} y^i$. In ...

Directed Edge Orientation with Out-Degree ConstraintGiven an undirected graph, determine the number of ways to orient all edges such that every vertex has an out-degree of exactly 1. The result should be modulo 998244353.For such an orientation to exist, the number of edges must exactly equal the number of vertices, i.e., m = n. Furthermore, ev ...

Mock Contest Problem 1 Problem Overview Converting the constraints reveals two key requirements for any valid set: Must include the maximum power of each prime factor of n Must contain at least one pair of distinct prime factors Since the number of prime factors is much smaller than log(n), brute force search works effectively. Approach: Incl ...

A. Ribbon Coloring Strategy Alice's optimal strategy is to color the ribbon in a repeating pattern like "123123...". Bob's optimal counter-strategy is to recolor the ribbon to the most frequent color. The most frequent color appears at least ⌈n/m⌉ times, leaving Bob with at most (n - ⌈n/m⌉) recoloring operations. Compare this value wi ...

Problem 1: Equalizing Elements via Modulo Problem Statement Given an array of integers, determine if it is possible to make all elements equal by repeatedly applying a modulo operation with an integer $x \ge 2$. In each step, every element $a_i$ is replaced by $a_i \bmod x$. Analysis The core constraint lies in the behavior of small numbers und ...

Holiday Reading A book has n pages. A student can read at most k pages per day over t vacation days. The maximum number of pages they can finish is the smaller of n and k * t. n = int(input()) k = int(input()) t = int(input()) print(min(n, k * t)) Shared Duty Schedule Two students clean on cycles of m and n days. The next time they coincide i ...