Thieves and Prisons

input/code.cpp: In function 'int main()':
input/code.cpp:9:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d%d", &n, &k, &m);
  ~~~~~^~~~~~~~~~~~~~~~~~~~~~
input/code.cpp:15:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf(" %c%d", &type[i], &a);
   ~~~~~^~~~~~~~~~~~~~~~~~~~~~~

#include <bits/stdc++.h>
using namespace std;
int n, k, m, upto, p[100010], inprison[100010], lastprisonbreak;
set<int> unassignedprisons;
char type[100010];
int A[100010];
int main()
{
	scanf("%d%d%d", &n, &k, &m);
	fill_n(inprison, n+1, -1);
	lastprisonbreak = -1;
	for (int i = 0; i < m; i++)
	{
		int a;
		scanf(" %c%d", &type[i], &a);
		A[i] = a;
		// Person a needs to be released from prison
		if (inprison[a] != -1)
		{
			auto it = unassignedprisons.lower_bound(inprison[a]);
			if (it != unassignedprisons.end())
			{
				p[inprison[a]] = p[*it];
				unassignedprisons.erase(it);
			}
			else if (lastprisonbreak < inprison[a])
			{
				p[inprison[a]] = upto;
				printf("IMPOSSIBLE\n");
				exit(0);
			}
			inprison[a] = -1;
		}
		if (type[i] == 'O')
		{
			lastprisonbreak = i;
			upto%=k;
			p[i] = ++upto;
			unassignedprisons.insert(i);
		}
		else
		{
			inprison[a] = i;
		}
	}
	upto %= k;
	upto++;
	for (int i = 1; i <= n; i++)
	{
		if (inprison[i] != -1)
		{
			auto it = unassignedprisons.lower_bound(inprison[i]);
			if (it != unassignedprisons.end())
			{
				p[inprison[i]] = p[*it];
				unassignedprisons.erase(it);
			}
			else p[inprison[i]] = upto;
		}
	}
	if (unassignedprisons.size())
	{
		printf("IMPOSSIBLE\n");
		exit(0);
	}
	for (int i = 0; i < m; i++)
	{
		printf("%d ", p[i]);
	}
	printf("\n");
}

Test 1

Group: 2, 4, 5

Verdict: ACCEPTED

Test 2

Group: 2, 4, 5

Verdict: ACCEPTED

Test 3

Group: 2, 4, 5

Verdict: ACCEPTED

Test 4

Group: 2, 4, 5

Verdict: ACCEPTED

Test 5

Group: 2, 4, 5

Verdict: ACCEPTED

Test 6

Group: 4, 5

Verdict: ACCEPTED

Test 7

Group: 4, 5

Verdict: ACCEPTED

Test 8

Group: 4, 5

Verdict: ACCEPTED

Test 9

Group: 1, 3, 4, 5

Verdict: WRONG ANSWER

Test 10

Group: 1, 3, 4, 5

Verdict: ACCEPTED

Test 11

Group: 1, 3, 4, 5

Verdict: ACCEPTED

Test 12

Group: 1, 3, 4, 5

Verdict: ACCEPTED

Test 13

Group: 1, 3, 4, 5

Verdict: ACCEPTED

Test 14

Group: 1, 3, 4, 5

Verdict: ACCEPTED

Test 15

Group: 1, 3, 4, 5

Verdict: ACCEPTED

Test 16

Group: 1, 3, 4, 5

Verdict: ACCEPTED

Test 17

Group: 1, 2, 3, 4, 5

Verdict: ACCEPTED

Test 18

Group: 1, 3, 4, 5

Verdict: ACCEPTED

Test 19

Group: 2, 5

Verdict: ACCEPTED

Test 20

Group: 2, 5

Verdict: WRONG ANSWER

Test 21

Group: 2, 5

Verdict: WRONG ANSWER

Test 22

Group: 5

Verdict: WRONG ANSWER

Test 23

Group: 5

Verdict: WRONG ANSWER

Test 24

Group: 3, 4, 5

Verdict: WRONG ANSWER

Test 25

Group: 3, 4, 5

Verdict: WRONG ANSWER

Test 26

Group: 3, 4, 5

Verdict: WRONG ANSWER

Test 27

Group: 3, 4, 5

Verdict: WRONG ANSWER

Test 28

Group: 4, 5

Verdict: ACCEPTED

Test 29

Group: 4, 5

Verdict: ACCEPTED

Test 30

Group: 4, 5

Verdict: ACCEPTED

Test 31

Group: 4, 5

Verdict: ACCEPTED

Test 32

Group: 2, 4, 5

Verdict: ACCEPTED

Test 33

Group: 2, 4, 5

Verdict: ACCEPTED

Test 34

Group: 2, 4, 5

Verdict: ACCEPTED

Test 35

Group: 2, 4, 5

Verdict: ACCEPTED

Test 36

Group: 3, 5

Verdict: WRONG ANSWER

Test 37

Group: 3, 5

Verdict: WRONG ANSWER

Test 38

Group: 3, 5

Verdict: WRONG ANSWER

Test 39

Group: 3, 5

Verdict: WRONG ANSWER

Test 40

Group: 5

Verdict: ACCEPTED

Test 41

Group: 5

Verdict: ACCEPTED

Test 42

Group: 5

Verdict: ACCEPTED

Test 43

Group: 5

Verdict: ACCEPTED

Test 44

Group: 2, 5

Verdict: ACCEPTED

Test 45

Group: 2, 5

Verdict: ACCEPTED

Test 46

Group: 2, 5

Verdict: ACCEPTED

Test 47

Group: 2, 5

Verdict: ACCEPTED