How shakawatullah-tanin/summation_from_1_to_n works
Purpose
Single-problem C++ solution repository for Codeforces/ICPC Assiut Sheet #1 problem “G. Summation from 1 to N.” It computes the sum of integers from 1 through a supplied N efficiently.
Entry Point
The executable starts in G_Summation_from_1_to_N.cpp, which contains the program’s main function, standard input handling, computation, and standard output.
Core Computation
G_Summation_from_1_to_N.cpp applies the closed-form arithmetic-series equation:
N * (N + 1) / 2
This replaces iterative summation, giving constant-time execution and avoiding loop-based timeout risks.
Data Boundary
Input crosses the program boundary through standard input as a single numeric value N; the computed sum is emitted through standard output. There are no files, databases, network calls, or persistent state.
Numeric Safety
G_Summation_from_1_to_N.cpp uses a 64-bit integer type (long long) for the input and result, protecting the multiplication and final sum from ordinary 32-bit integer overflow for the problem’s expected range.
Runtime and Dependencies
The solution is a standalone native C++ console program. Its only expected dependencies are the C++ standard library and a competitive-programming compiler/runtime environment. No external services or infrastructure are involved.
Main entry points: G_Summation_from_1_to_N.cpp main()
Components 5
Other components
- Standard Input · Provides one numeric value N.
- main() · Reads N, computes the sum, and writes the result.
G_Summation_from_1_to_N.cpp - Arithmetic Series Formula · Computes N * (N + 1) / 2 using long long.
G_Summation_from_1_to_N.cpp - Standard Output · Emits the computed sum.
- C++ Standard Runtime · Provides standard library and console I/O support.
Connections 5
- Standard Input → main(): read N
- main() → Arithmetic Series Formula: N
- Arithmetic Series Formula → main(): long long sum
- main() → Standard Output: write sum
- C++ Standard Runtime → main(): runs