Another Contest 5 Problem 3 - Cutting Cheese Costs

Points: 5 (partial)

Time limit: 1.0s

Memory limit: 256M

Problem type

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

Tudor has $K$ $K$ 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 $N$ $N$ blocks of cheese, compute the minimum amount of money he must spend.

Constraints

$1 \le N \le 10^5$ $1 \leq N \leq 10^{5}$

$0 \le K \le N$ $0 \leq K \leq N$

$1 \le d_i \le p_i \le 10^9$ $1 \leq d_{i} \leq p_{i} \leq 10^{9}$

Input Specification

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

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

Output Specification

Output the minimum amount of money Tudor must spend.

Sample Input

Copy

2 1
100 0
10 10

Sample Output

Copy

Comments

3

tappbros commented on July 24, 2020, 8:59 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...

16

Kirito commented on July 24, 2020, 11:00 p.m.

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

3

notpeachay420 commented on Oct. 30, 2020, 5:11 p.m.

ohhhh that makes more sense

1

Pleedoh commented on Oct. 21, 2019, 2:19 a.m. ← edited →

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

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

6

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

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