Adding Solutions

Basic Debugging

Choosing a Language

Contest Strategy

Contests

Contributing

C++ With the Command Line

Data Types

How to Debug

Debugging C++

Expected Knowledge

Fast Input & Output

(Optional) C++ - Writing Generic Code

Input & Output

Introduction to Competitive Programming

(Optional) C++ - Lambda Expressions

Resources: Learning to Code

Introducing Modules

Olympiads

How to Practice

Resources: Competitive Programming

Resources: USA-Specific

Running Code Locally

Running Code Online

USACO Camp

USACO FAQs

USACO Monthlies

Using This Guide

Working With MDX

Ad Hoc Problems

Casework

Complete Search with Recursion

Additional Practice for USACO Bronze

Basic Complete Search

Introduction to Data Structures

Introduction to Graphs

Introduction to Greedy Algorithms

Introduction to Sets & Maps

Introduction to Sorting

Rectangle Geometry

Simulation

Time Complexity

Binary Search

Binary Search on a Sorted Array

Additional Practice for USACO Silver

Flood Fill

Introduction to Functional Graphs

Graph Traversal

Greedy Algorithms with Sorting

Intro to Bitwise Operators

Introduction to Tree Algorithms

More on Prefix Sums

Introduction to Prefix Sums

Priority Queues

Custom Comparators and Coordinate Compression

Two Pointers

DP on Trees - Solving For All Roots

Combinatorics

Additional Practice for USACO Gold

(Optional) Sorted Sets with Custom Comparators

Bitmask DP

Range DP

DP on Trees - Introduction

Disjoint Set Union

Digit DP

Divisibility

Hashing

(Optional) Hashmaps

Introduction to DP

More Operations on Sorted Sets

Knapsack DP

(Optional) LCA with Euler Tour

Longest Increasing Subsequence

Minimum Spanning Trees

(Optional) Meet In The Middle

Modular Arithmetic

Point Update Range Sum

Paths on Grids

Shortest Paths with Non-Negative Edge Weights

Sliding Window

Stacks

Optimizing Unimodal Functions

Topological Sort

(Optional) Euler Tour Technique

Shortest Paths with Unweighted Edges

2D Range Queries

Binary Jumping

(Optional) Bitsets

Centroid Decomposition

Additional Practice for USACO Platinum

Convex Hull

Convex Hull Trick

Divide & Conquer - DP

Divide & Conquer - SRQ

Sum over Subsets DP

Geometry Primitives

Heavy-Light Decomposition

Matrix Exponentiation

Small-To-Large Merging

Inclusion-Exclusion Principle

Using Divide & Conquer to answer offline or online range queries on a static array.

problem

FocusProblem

Warning

Resource

Resources

title

Optional

problems

Problems

2014 - Secret

"use strict";
const {Fragment: _Fragment, jsx: _jsx, jsxs: _jsxs} = arguments[0];
const frontmatter = undefined;
function _createMdxContent(props) {
 const _components = {
 a: "a",
 code: "code",
 h2: "h2",
 p: "p",
 pre: "pre",
 strong: "strong",
 ...props.components
 }, {HeaderLink, IncompleteSection, MATHSPAN} = _components;
 if (!HeaderLink) _missingMdxReference("HeaderLink", true);
 if (!IncompleteSection) _missingMdxReference("IncompleteSection", true);
 if (!MATHSPAN) _missingMdxReference("MATHSPAN", true);
 return _jsxs(_Fragment, {
 children: [_jsx(IncompleteSection, {}), "\n", _jsxs(_components.h2, {
 id: "implementation",
 children: [_jsx(_components.a, {
 "aria-hidden": "true",
 tabIndex: "-1",
 className: "anchor before",
 href: "#implementation",
 children: _jsx(HeaderLink, {})
 }), "Implementation"]
 }), "\n", _jsxs(_components.p, {
 children: [_jsx(_components.strong, {
 children: "Time Complexity:"
 }), " ", _jsx(MATHSPAN, {
 className: "language-math math-inline",
 latex: "\\mathcal{O}(N \\log N)",
 children: "<math xmlns=\"http://www.w3.org/1998/Math/MathML\"><semantics><mrow><mi mathvariant=\"script\">O</mi><mo stretchy=\"false\">(</mo><mi>N</mi><mi>log</mi><mo>⁡</mo><mi>N</mi><mo stretchy=\"false\">)</mo></mrow><annotation encoding=\"application/x-tex\">\\mathcal{O}(N \\log N)</annotation></semantics></math>O(NlogN)"
 })]
 }), "\n", _jsx(_components.pre, {
 children: _jsx(_components.code, {
 className: "language-cpp",
 children: "#include \"secret.h\"\n\nint prefix[1000][1000], n;\n\nvoid populate(int L, int R, int A[]) {\n\tint mid = (L + R) / 2;\n\tprefix[mid][mid] = A[mid];\n\tprefix[mid + 1][mid + 1] = A[mid + 1];\n\n\tfor (int i = mid + 2; i <= R; i++)\n\t\tprefix[mid + 1][i] = Secret(prefix[mid + 1][i - 1], A[i]);\n\tfor (int i = mid - 1; i >= L; i--)\n\t\tprefix[mid][i] = Secret(A[i], prefix[mid][i + 1]);\n\n\tif (L < mid) populate(L, mid, A);\n\tif (mid + 1 < R) populate(mid + 1, R, A);\n}\n\nvoid Init(int N, int A[]) {\n\tn = N;\n\tpopulate(0, N - 1, A);\n}\n\nint Query(int L, int R) {\n\tint a = 0, b = n - 1;\n\n\twhile (a != b) {\n\t\tint mid = (a + b) / 2;\n\t\tif (mid >= L && mid < R) return Secret(prefix[mid][L], prefix[mid + 1][R]);\n\t\telse if (mid == R) return prefix[mid][L];\n\t\telse if (mid < L) a = mid + 1;\n\t\telse b = mid;\n\t}\n\n\treturn prefix[a][a];\n}\n"
 })
 })]
 });
}
function MDXContent(props = {}) {
 const {wrapper: MDXLayout} = props.components || ({});
 return MDXLayout ? _jsx(MDXLayout, {
 ...props,
 children: _jsx(_createMdxContent, {
 ...props
 })
 }) : _createMdxContent(props);
}
return {
 frontmatter,
 default: MDXContent
};
function _missingMdxReference(id, component) {
 throw new Error("Expected " + (component ? "component" : "object") + " `" + id + "` to be defined: you likely forgot to import, pass, or provide it.");
}

Secret

IncompleteSection

This section is not complete.

Implementation

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