Another Contest 5 Problem 3 - Cutting Cheese Costs

View as PDF

Submit solution


Points: 5 (partial)
Time limit: 1.0s
Memory limit: 256M

Problem type
Allowed languages
Ada, Assembly, Awk, Brain****, C, C#, C++, COBOL, CommonLisp, D, Dart, F#, Forth, Fortran, Go, Groovy, Haskell, Intercal, Java, JS, Kotlin, Lisp, Lua, Nim, ObjC, OCaml, Octave, Pascal, Perl, PHP, Pike, Prolog, Python, Racket, Ruby, Rust, Scala, Scheme, Sed, Swift, TCL, Text, Turing, VB, Zig

Tudor is buying N blocks of cheese. Each block of cheese has a regular price and a discounted price.

Tudor has K coupons that allow him to buy a block of cheese for the discounted price instead of the regular price. Each coupon can be used for exactly one block of cheese.

Given that Tudor wants to buy all N blocks of cheese, compute the minimum amount of money he must spend.

Constraints

1 \le N \le 10^5

0 \le K \le N

1 \le d_i \le p_i \le 10^9

Input Specification

The first line contains two space separated integers, N and K.

The next N lines each contain two space separated integers, p_i and d_i representing the regular price and discounted price of block i, respectively.

Output Specification

Output the minimum amount of money Tudor must spend.

Sample Input

2 1
100 0
10 10

Sample Output

10

Comments


  • 0
    tappbros  commented on July 24, 2020, 4:59 p.m. edited

    This has nothing to do with cutting cheese. What. I mean, I know it's a block of cheese which you can cut, but, like...


    • 3
      Kirito  commented on July 24, 2020, 7:00 p.m.

      It is not the cheese that is being cut, but the price of said cheese.


  • 2
    Pleedoh  commented on Oct. 20, 2019, 10:19 p.m. edited

    Can anyone help me with WA (Presentation Error, check your whitespace)?

    I literally just output the answer, there is no whitespace...


    • 4
      Tzak  commented on Oct. 21, 2019, 12:27 a.m.

      You should place a \n character at the end of your output.