Nyist OJ 448 max (basic)

Maximum search time limit: 1000 MS | memory limit: 65535 kb difficulty: 2

Description

Delete M numbers in integer n so that the remaining numbers are the largest in the original order,

For example, when n = 92081346718538 and M = 10, the new maximum number is 9888.

 

Input

Enter a positive integer T in the first line, indicating that there are T groups of test data.
Each group of test data occupies one row, each row has two numbers n, m (N may be a large integer, but its number of digits does not exceed 100 bits, and ensure that the first data is not 0, M is less than the number of digits of the integer N)

Output

The output of each group of test data occupies one row, and the remaining number is the largest new number in the original order.

Sample Input

292081346718538 101008908 5

Sample output

988898

Source

Adaptation of question 2 in the sixth itat semi-finals B

Uploaded

ACM _ Zhao minghao

This question is a general basic question, water question, but it is also easy to make mistakes. If you do not understand the question carefully, it is easy to contribute wa. At first, I did not clarify the meaning of the question, I thought it was to directly delete a few digits and find the maximum value. Then I used a sort directly, sorted in the order from large to small, and then output the first M bit, the sample can also pass .. Then I contributed wa several times. Then I took a closer look at the question and asked me to delete M numbers, and then I had the largest number in the original order. In this case, I also had some technical skills;

We can see that some great gods directly use the idea of Dynamic Planning (I am still a DP cainiao ..), Here, two loops are directly nested to find the maximum value in the m + 1 range, and then output the maximum value, and use a variable to mark the position of the maximum value; find the n-m maximum.

This kind of thinking should be mastered and will be used in other places in the future;

The following code is simplified:

# Include <cstdio> # include <cstring> int main () {int T, M, Len, Max; char s [101]; scanf ("% d ", & T); While (t --) {scanf ("% S % d", S, & M); Len = strlen (s); For (INT I = 0, j = 0; m <Len; m ++) // You Can See That J is assigned-1; {max = 0; while (j <= m) // ensure the number of digits {If (s [J]> MAX) {max = s [J]; I = J; // mark the maximum position} J ++; // search down} J = I + 1; printf ("% C", s [I]);} printf ("\ n");} return 0 ;}