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, lastopened[100010];
char type[100010];
int A[100010];
queue<int> occurrences[100010], breaks;
int main()
{
	scanf("%d%d%d", &n, &k, &m);
	fill_n(inprison, n+1, -1);
	fill_n(lastopened, k+1, -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
		occurrences[a].push(i);
		if (type[i] == 'O') breaks.push(i);
	}
	priority_queue<pair<int, int>, vector<pair<int, int> >, greater<pair<int, int> > > pq;
	for (int i = 0; i < m; i++)
	{
		int a = A[i];
		occurrences[a].pop();
		if (type[i] == 'O')
		{
			// Opening a prison
			upto %= k;
			p[i] = ++upto;
			int l = lastopened[upto];
			lastopened[upto] = i;
			breaks.pop();
			int nexbreak = 1e9;
			if (breaks.size()) nexbreak = breaks.front();
			//printf("%d %lu - %d\n", i, pq.size(), nexbreak);
			if (pq.empty() || pq.top().first <= i || pq.top().second < l) // what a shame
			{
				printf("IMPOSSIBLE\n");
				return 0;
			}
			do
			{
			//	printf(" %d %d\n", pq.top().first, pq.top().second);
				p[pq.top().second] = upto;
				pq.pop();
			}
			while (pq.size() && pq.top().first <= nexbreak);
		}
		else
		{
			pq.push({occurrences[a].size() ? occurrences[a].front() : 1e9, i});
		}
	}
	if (pq.size() && pq.top().first != 1e9)
	{
		printf("IMPOSSIBLE\n");
		return 0;
	}
	for (int i = 0; i < m; i++)
	{
		p[i] = max(p[i], 1);
		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: ACCEPTED

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: ACCEPTED

Test 21

Group: 2, 5

Verdict: ACCEPTED

Test 22

Group: 5

Verdict: ACCEPTED

Test 23

Group: 5

Verdict: ACCEPTED

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