Mock CCC '18 Contest 1 J5/S3 - A Simulation Problem

Points: 7 (partial)

Time limit: 0.16s

Java 0.6s

Python 0.6s

Memory limit: 1G

Problem type

Consider the following function:

function(N):
    # in some programming languages, 64-bit integers will be required to represent "threshold"
    threshold = N*(N-1)/2
    K = 1
    # in some programming languages, 64-bit integers will be required to represent "count"
    count = 0
    while K < N:
        L = K+1
        print K
        while L <= N:
            count += 1
            L += 1
            if 2 * count >= threshold:
                exit function
        K += 1

Given $N$ ~N~, compute the last number this function prints out.

Constraints

$2 \le N \le 10^9$ ~2 \le N \le 10^9~

Input Specification

The input consists of a single line containing the integer $N$ ~N~.

Output Specification

Print, on a single line, the last number this function will print out.

Sample Input 1

Sample Output 1

Sample Input 2

Sample Output 2

Sample Input 3

Sample Output 3

Sample Input 4

Sample Output 4

Sample Input 5

290976843

Sample Output 5

85225144

Comments

0

gavin_chen commented on May 29, 2022, 2:58 p.m. ← edit 2 →

Using the code the problem gave inputting 5 outputted 2 but using the editorial inputting 5 outputted 1? can someone tell me how the function the problem gave us works please? :) edit: nvm its not $N-1$ ~N-1~ to 1 its $N$ ~N~ to 1