Snippet Usage Guide - C++ Algorithm Snippets

Understanding Snippet Triggers

Every snippet in the library is triggered by typing its filename (without the .cpp extension) followed by your editor’s autocomplete trigger.

Naming Convention

Snippets follow a consistent naming pattern:

{category}_{algorithm}_{variant}

Examples:

graph_dijkstra_std - Standard Dijkstra algorithm from the graph category
string_kmp_std - Standard KMP pattern matching from string category
range_query_segment_tree_lazy_compress - Compressed lazy segment tree from range query category

VS Code Usage

Triggering Snippets

Type the Snippet Prefix

Start typing the snippet name in a .cpp file:

graph_dij

Select from Autocomplete

VS Code will show matching snippets in the autocomplete menu. Use arrow keys to select and press Enter or Tab.

Press Ctrl+Space (Windows/Linux) or Cmd+Space (macOS) to manually trigger autocomplete.

Navigate Placeholders

Some snippets contain placeholders marked with $1, $2, etc. Press Tab to jump between them.

IntelliSense Configuration

For optimal snippet experience, configure your settings.json:

settings.json

{
  "editor.quickSuggestions": {
    "other": true,
    "comments": false,
    "strings": false
  },
  "editor.suggestSelection": "first",
  "editor.tabCompletion": "on",
  "editor.acceptSuggestionOnEnter": "on",
  "editor.snippetSuggestions": "top",
  "[cpp]": {
    "editor.suggest.snippetsPreventQuickSuggestions": false
  }
}

"editor.snippetSuggestions": "top" ensures snippets appear at the top of autocomplete suggestions.

Keyboard Shortcuts

Action	Windows/Linux	macOS
Trigger autocomplete	`Ctrl+Space`	`Cmd+Space`
Next placeholder	`Tab`	`Tab`
Previous placeholder	`Shift+Tab`	`Shift+Tab`
Accept suggestion	`Enter` or `Tab`	`Enter` or `Tab`
Dismiss suggestions	`Esc`	`Esc`

Custom Keybindings

Add to your keybindings.json for even faster workflow:

keybindings.json

[
  {
    "key": "ctrl+j",
    "command": "jumpToNextSnippetPlaceholder",
    "when": "editorTextFocus && hasNextTabstop"
  },
  {
    "key": "ctrl+k",
    "command": "jumpToPrevSnippetPlaceholder",
    "when": "editorTextFocus && hasPrevTabstop"
  }
]

Vim/Neovim Usage

UltiSnips Configuration

Add to your .vimrc or init.vim:

" UltiSnips trigger configuration
let g:UltiSnipsExpandTrigger="<tab>"
let g:UltiSnipsJumpForwardTrigger="<c-j>"
let g:UltiSnipsJumpBackwardTrigger="<c-k>"
let g:UltiSnipsListSnippets="<c-l>"

" Snippet directory
let g:UltiSnipsSnippetDirectories=["UltiSnips"]

" Edit snippets in vertical split
let g:UltiSnipsEditSplit="vertical"

Triggering Snippets

Enter Insert Mode

Press i or a to enter insert mode in your .cpp file.

Type the Snippet Prefix

Type the complete or partial snippet name:

graph_dijkstra_std

Press Tab

Press Tab to expand the snippet. The entire code will be inserted at the cursor position.

Navigate Placeholders

Use Ctrl+j and Ctrl+k to jump between placeholders (if configured as shown above).

Snippet Listing

To see all available snippets while editing:

:UltiSnipsEdit

Or use the list trigger (Ctrl+l with the above configuration).

Advanced Vim Configuration

For completion menu integration with coc.nvim:

" Make <tab> used for trigger completion, completion confirm,
" snippet expand and jump
inoremap <silent><expr> <TAB>
  \ coc#pum#visible() ? coc#_select_confirm() :
  \ coc#expandableOrJumpable() ?
  \ "\<C-r>=coc#rpc#request('doKeymap', ['snippets-expand-jump',''])\<CR>" :
  \ CheckBackspace() ? "\<TAB>" :
  \ coc#refresh()

function! CheckBackspace() abort
  let col = col('.') - 1
  return !col || getline('.')[col - 1]  =~# '\s'
endfunction

let g:coc_snippet_next = '<tab>'

Snippet Categories and Usage Patterns

Template Snippets

Always use a template as your starting point:

template_std
// Full-featured template with utilities

Graph Snippets

Graph algorithms require the base graph structure:

// Order matters!
graph_graph          // Base structure
graph_digraph        // Or graph_undigraph
graph_dijkstra_std   // Your algorithm

Always include graph_graph before any graph class or algorithm snippet.

Data Structure Snippets

Most data structures are self-contained:

data_structure_trie_dynamic
// Complete Trie implementation
// Ready to use immediately

Utility Snippets

Add utilities anywhere in your code:

misc_debug              // Debug macros
misc_loops              // Loop shortcuts
misc_directions         // 2D grid navigation
numeric_mint_compress   // Modular arithmetic

Snippet Dependencies

Common Dependencies

Some snippets require others to work:

Graph Algorithms

Required:

graph_graph (base class)
graph_digraph OR graph_undigraph

Then use:

graph_dijkstra_std
graph_bellman_ford
graph_floyd_warshall
graph_kruskal
Any other graph algorithm

Segment Tree with Lazy Propagation

Self-contained:

range_query_segment_tree_lazy_full
range_query_segment_tree_lazy_compress

No dependencies needed.

String Algorithms

Self-contained:

All string snippets are independent
string_kmp_std
string_rabin_karp_std
string_z_algorithm_std

Modular Arithmetic

Use one of:

numeric_mint_full (comprehensive)
numeric_mint_medium (balanced)
numeric_mint_compress (minimal)

Then optionally add:

combinatorics_ncr_compress (binomial coefficients)
math_factorial

Multi-Snippet Workflow

Building Complex Solutions

For problems requiring multiple algorithms:

Start with Template

template_std

Add Core Structures

Add any base structures (graph, tree, etc.):

graph_graph
graph_undigraph

Add Algorithms

Insert algorithm snippets in order:

graph_dijkstra_std
data_structure_trie_dynamic

Add Utilities

Include helpful utilities:

misc_debug
misc_loops

Example: Complex Problem

Solving a problem with graphs, modular arithmetic, and combinatorics:

template_std                    // 1. Base template
graph_graph                     // 2. Graph structure
graph_undigraph                 // 3. Undirected graph
tree_diameter                   // 4. Tree algorithm
numeric_mint_compress           // 5. Modular arithmetic
combinatorics_ncr_compress      // 6. Combinatorics
misc_debug                      // 7. Debug utilities

Snippet Customization

Modifying Generated Snippets

VS Code

Open snippet file:
- Windows: %APPDATA%\Code\User\snippets\cpp.json
- Linux: ~/.config/Code/User/snippets/cpp.json
- macOS: ~/Library/Application Support/Code/User/snippets/cpp.json
Edit the snippet JSON:

"graph_dijkstra_std": {
    "prefix": "dijkstra",  // Change trigger
    "body": [
        "// Your modified code here"
    ]
}

Your changes will be overwritten if you run generate_vscode_snippets.py again.

Vim/Neovim

Open snippet file:

:e ~/.vim/UltiSnips/cpp/cpp_generate.snippets

Modify the snippet:

snippet dijkstra "dijkstra custom"
// Your custom implementation
endsnippet

Creating Custom Snippets

To avoid overwriting, create a separate file:

VS Code

Create cpp-custom.json in your snippets directory:

{
  "My Custom Dijkstra": {
    "prefix": "my_dijkstra",
    "body": [
      "// Custom implementation"
    ]
  }
}

Vim/Neovim

Create ~/.vim/UltiSnips/cpp/custom.snippets:

snippet my_dijkstra "My custom dijkstra"
// Custom implementation
endsnippet

Performance Tips

Load Selectively

Only include snippets you need. Avoid loading entire categories unnecessarily.

Use Compressed Variants

When available, use _compress variants:

numeric_mint_compress
string_hashing_static_compress

They compile faster and use less memory.

Template First

Always start with a template. It includes essential optimizations:

Fast I/O
Compiler pragmas
Common macros

Know Your Variants

Many algorithms have multiple variants:

_std - Standard implementation
_full - Feature-complete
_compress - Minimal version

Choose based on problem requirements.

Troubleshooting

Snippets Not Appearing

VS Code: Snippets don't show up

Check file extension is .cpp
Verify cpp.json exists in snippets directory
Restart VS Code
Check settings.json has snippets enabled
Try manual trigger: Ctrl+Space

Vim: Tab doesn't expand snippet

Verify UltiSnips is installed: :echo exists('g:UltiSnipsExpandTrigger')
Check trigger key: :echo g:UltiSnipsExpandTrigger
Ensure snippet file exists: :!ls ~/.vim/UltiSnips/cpp/
Try listing snippets: :UltiSnipsEdit

Compilation errors after using snippet

Check if snippet requires dependencies (e.g., graph_graph)
Ensure correct order of snippets
Verify C++ standard: compile with -std=c++17
Check for namespace conflicts

Next Steps

Competitive Programming

Learn best practices and optimization strategies

Templates Overview

Explore all available template options

Getting Started

Core Concepts

​Understanding Snippet Triggers

​Naming Convention

​VS Code Usage

​Triggering Snippets

​IntelliSense Configuration

​Keyboard Shortcuts

​Custom Keybindings

​Vim/Neovim Usage

​UltiSnips Configuration

​Triggering Snippets

​Snippet Listing

​Advanced Vim Configuration

​Snippet Categories and Usage Patterns

​Template Snippets

​Graph Snippets

​Data Structure Snippets

​Utility Snippets

​Snippet Dependencies

​Common Dependencies

​Multi-Snippet Workflow

​Building Complex Solutions

​Example: Complex Problem

​Snippet Customization

​Modifying Generated Snippets

​VS Code

​Vim/Neovim

​Creating Custom Snippets

​VS Code

​Vim/Neovim

​Performance Tips

Load Selectively

Use Compressed Variants

Template First

Know Your Variants

​Troubleshooting

​Snippets Not Appearing

​Next Steps

Competitive Programming

Templates Overview

Build docs developers (and LLMs) love

Understanding Snippet Triggers

Naming Convention

VS Code Usage

Triggering Snippets

IntelliSense Configuration

Keyboard Shortcuts

Custom Keybindings

Vim/Neovim Usage

UltiSnips Configuration

Triggering Snippets

Snippet Listing

Advanced Vim Configuration

Snippet Categories and Usage Patterns

Template Snippets

Graph Snippets

Data Structure Snippets

Utility Snippets

Snippet Dependencies

Common Dependencies

Multi-Snippet Workflow

Building Complex Solutions

Example: Complex Problem

Snippet Customization

Modifying Generated Snippets

VS Code

Vim/Neovim

Creating Custom Snippets

VS Code

Vim/Neovim

Performance Tips

Troubleshooting

Snippets Not Appearing

Next Steps