Submission #701622

#	Submission time	Handle	Problem	Language	Result	Execution time	Memory
701622	2023-02-21T15:30:23 Z	lovrot	Event Hopping (BOI22_events)	C++17	100 / 100	277 ms	36944 KB

events

#include <cstdio>
#include <vector> 
#include <queue>
#include <stack> 
#include <algorithm> 
#include <cstring>
#include <map>

#define X first
#define Y second
#define pb push_back 

using namespace std; 

typedef pair<int, int> pii; 

const int LOG = 18; 
const int OFF = 1 << LOG; 

int n, t; 
int S[OFF], E[OFF], up[OFF][LOG], T[2 * OFF]; 

vector<int> vri, sweep;  
map<int, int> mp; 

int merge(int a, int b) { 
	if(a == -1 || b == -1) return a > -1 ? a : b; 
	return S[a] < S[b] ? a : b; 
}

void update(int a, int val) {
	a += OFF; 
	T[a] = merge(T[a], val); 
	a /= 2;
	while(a) {
		T[a] = merge(T[2 * a], T[2 * a + 1]); 
		a /= 2; 
	}
}

int query(int l, int r, int lo = 0, int hi = OFF, int x = 1) {
	if(r <= lo || hi <= l) return -1;
	if(l <= lo && hi <= r) return T[x];
	int mi = (lo + hi) / 2;
	return merge(query(l, r, lo, mi, 2 * x), query(l, r, mi, hi, 2 * x + 1)); 
}

bool comp(int a, int b) {
	return E[a] == E[b] ? S[a] < S[b] : E[a] < E[b];
}

pii climb(int a, int b) {
	int res = 0; 
	for(int i = LOG - 1; i >= 0; i--) {
		if(up[b][i] == -1) continue; 
		else if(E[a] < S[up[b][i]]) { 
			b = up[b][i]; 
			res += 1 << i; 
		}
	}
	if(E[a] < S[b] && up[b][0] != -1) {
		b = up[b][0]; 
		res++;
	}
	return {b, res}; 
}

int main() {
	memset(up, -1, sizeof(up)); 
	memset(T, -1, sizeof(T));

	scanf("%d%d", &n, &t); 
	for(int i = 0; i < n; i++) {
		scanf("%d%d", S + i, E + i); 
		vri.pb(S[i]);
		vri.pb(E[i]); 
		//vri.pb(E[i] + 1); 
	}
	
	sort(vri.begin(), vri.end());
	vri.erase(unique(vri.begin(), vri.end()), vri.end());  
	
	for(int i = 0; i < (int) vri.size(); i++) mp[vri[i]] = i; 
	
	for(int i = 0; i < n; i++) {
		S[i] = mp[S[i]]; 
		E[i] = mp[E[i]]; 
		//printf("Si = %d Ei = %d\n", S[i] + 1, E[i] + 1);
		sweep.pb(i); 
	}

	sort(sweep.begin(), sweep.end(), comp); 

	for(int i : sweep) {
		up[i][0] = query(S[i], E[i] + 1); 
		update(E[i], i); 
		if(S[i] <= S[up[i][0]]) up[i][0] = -1;
		//printf("UP%d = %d\n", i, up[i][0]);
	}

	for(int j = 1; j < LOG; j++)
		for(int i = 0; i < n; i++)
			if(up[i][j - 1] != -1) up[i][j] = up[up[i][j - 1]][j - 1]; 

	for(int i = 0; i < t; i++) {
		int s, e; 
		scanf("%d%d", &s, &e); 
		//printf("%d %d\n", s, e);
		s--; 
		e--; 
		// if(t >= 20) continue;
		if(e == s) {
			printf("0\n");
		} else if(E[e] < E[s]) {
			printf("impossible\n");  
		} else {
			pii r = climb(s, e); 
			if(S[r.X] <= E[s] && E[s] <= E[r.X]) printf("%d\n", r.Y + 1); 
			else printf("impossible\n");
		}
	}
	return 0; 
}

Compilation message

events.cpp: In function 'int main()':
events.cpp:72:7: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   72 |  scanf("%d%d", &n, &t);
      |  ~~~~~^~~~~~~~~~~~~~~~
events.cpp:74:8: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   74 |   scanf("%d%d", S + i, E + i);
      |   ~~~~~^~~~~~~~~~~~~~~~~~~~~~
events.cpp:107:8: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  107 |   scanf("%d%d", &s, &e);
      |   ~~~~~^~~~~~~~~~~~~~~~

Subtask #1

10.0 / 10.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	9 ms	20820 KB	Output is correct
2	Correct	179 ms	31140 KB	Output is correct
3	Correct	192 ms	31704 KB	Output is correct
4	Correct	227 ms	31580 KB	Output is correct
5	Correct	191 ms	32180 KB	Output is correct
6	Correct	208 ms	32628 KB	Output is correct
7	Correct	198 ms	32764 KB	Output is correct
8	Correct	199 ms	36920 KB	Output is correct
9	Correct	196 ms	36824 KB	Output is correct
10	Correct	190 ms	31936 KB	Output is correct
11	Correct	216 ms	33908 KB	Output is correct
12	Correct	135 ms	31324 KB	Output is correct

Subtask #2

10.0 / 10.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	9 ms	20820 KB	Output is correct
2	Correct	10 ms	20812 KB	Output is correct
3	Correct	9 ms	20820 KB	Output is correct
4	Correct	9 ms	20832 KB	Output is correct
5	Correct	10 ms	20824 KB	Output is correct
6	Correct	10 ms	20816 KB	Output is correct
7	Correct	12 ms	20956 KB	Output is correct
8	Correct	9 ms	20948 KB	Output is correct
9	Correct	9 ms	20824 KB	Output is correct

Subtask #3

15.0 / 15.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	9 ms	20820 KB	Output is correct
2	Correct	10 ms	20812 KB	Output is correct
3	Correct	9 ms	20820 KB	Output is correct
4	Correct	9 ms	20832 KB	Output is correct
5	Correct	10 ms	20824 KB	Output is correct
6	Correct	10 ms	20816 KB	Output is correct
7	Correct	12 ms	20956 KB	Output is correct
8	Correct	9 ms	20948 KB	Output is correct
9	Correct	9 ms	20824 KB	Output is correct
10	Correct	8 ms	20820 KB	Output is correct
11	Correct	9 ms	20772 KB	Output is correct
12	Correct	9 ms	20864 KB	Output is correct
13	Correct	10 ms	20820 KB	Output is correct
14	Correct	9 ms	20840 KB	Output is correct
15	Correct	9 ms	20832 KB	Output is correct
16	Correct	9 ms	20888 KB	Output is correct
17	Correct	10 ms	20948 KB	Output is correct
18	Correct	9 ms	20820 KB	Output is correct
19	Correct	53 ms	22800 KB	Output is correct
20	Correct	44 ms	22704 KB	Output is correct
21	Correct	53 ms	22936 KB	Output is correct
22	Correct	40 ms	23020 KB	Output is correct
23	Correct	42 ms	23092 KB	Output is correct
24	Correct	42 ms	23060 KB	Output is correct
25	Correct	45 ms	22732 KB	Output is correct

Subtask #4

15.0 / 15.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	9 ms	20820 KB	Output is correct
2	Correct	10 ms	20812 KB	Output is correct
3	Correct	9 ms	20820 KB	Output is correct
4	Correct	9 ms	20832 KB	Output is correct
5	Correct	10 ms	20824 KB	Output is correct
6	Correct	10 ms	20816 KB	Output is correct
7	Correct	12 ms	20956 KB	Output is correct
8	Correct	9 ms	20948 KB	Output is correct
9	Correct	9 ms	20824 KB	Output is correct
10	Correct	9 ms	20820 KB	Output is correct
11	Correct	9 ms	20776 KB	Output is correct
12	Correct	9 ms	20820 KB	Output is correct
13	Correct	12 ms	20820 KB	Output is correct
14	Correct	10 ms	20820 KB	Output is correct
15	Correct	10 ms	20776 KB	Output is correct
16	Correct	9 ms	20960 KB	Output is correct
17	Correct	12 ms	20852 KB	Output is correct
18	Correct	16 ms	20820 KB	Output is correct
19	Correct	163 ms	29892 KB	Output is correct
20	Correct	140 ms	29128 KB	Output is correct
21	Correct	163 ms	29828 KB	Output is correct
22	Correct	171 ms	31700 KB	Output is correct
23	Correct	232 ms	34604 KB	Output is correct
24	Correct	212 ms	34600 KB	Output is correct
25	Correct	56 ms	24512 KB	Output is correct

Subtask #5

20.0 / 20.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	231 ms	31040 KB	Output is correct
2	Correct	203 ms	31644 KB	Output is correct
3	Correct	205 ms	31552 KB	Output is correct
4	Correct	222 ms	36864 KB	Output is correct
5	Correct	207 ms	31932 KB	Output is correct
6	Correct	277 ms	36412 KB	Output is correct
7	Correct	249 ms	36472 KB	Output is correct
8	Correct	240 ms	36612 KB	Output is correct
9	Correct	209 ms	34600 KB	Output is correct
10	Correct	239 ms	36048 KB	Output is correct
11	Correct	232 ms	35860 KB	Output is correct
12	Correct	253 ms	36080 KB	Output is correct

Subtask #6

30.0 / 30.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	9 ms	20820 KB	Output is correct
2	Correct	179 ms	31140 KB	Output is correct
3	Correct	192 ms	31704 KB	Output is correct
4	Correct	227 ms	31580 KB	Output is correct
5	Correct	191 ms	32180 KB	Output is correct
6	Correct	208 ms	32628 KB	Output is correct
7	Correct	198 ms	32764 KB	Output is correct
8	Correct	199 ms	36920 KB	Output is correct
9	Correct	196 ms	36824 KB	Output is correct
10	Correct	190 ms	31936 KB	Output is correct
11	Correct	216 ms	33908 KB	Output is correct
12	Correct	135 ms	31324 KB	Output is correct
13	Correct	9 ms	20820 KB	Output is correct
14	Correct	10 ms	20812 KB	Output is correct
15	Correct	9 ms	20820 KB	Output is correct
16	Correct	9 ms	20832 KB	Output is correct
17	Correct	10 ms	20824 KB	Output is correct
18	Correct	10 ms	20816 KB	Output is correct
19	Correct	12 ms	20956 KB	Output is correct
20	Correct	9 ms	20948 KB	Output is correct
21	Correct	9 ms	20824 KB	Output is correct
22	Correct	8 ms	20820 KB	Output is correct
23	Correct	9 ms	20772 KB	Output is correct
24	Correct	9 ms	20864 KB	Output is correct
25	Correct	10 ms	20820 KB	Output is correct
26	Correct	9 ms	20840 KB	Output is correct
27	Correct	9 ms	20832 KB	Output is correct
28	Correct	9 ms	20888 KB	Output is correct
29	Correct	10 ms	20948 KB	Output is correct
30	Correct	9 ms	20820 KB	Output is correct
31	Correct	53 ms	22800 KB	Output is correct
32	Correct	44 ms	22704 KB	Output is correct
33	Correct	53 ms	22936 KB	Output is correct
34	Correct	40 ms	23020 KB	Output is correct
35	Correct	42 ms	23092 KB	Output is correct
36	Correct	42 ms	23060 KB	Output is correct
37	Correct	45 ms	22732 KB	Output is correct
38	Correct	9 ms	20820 KB	Output is correct
39	Correct	9 ms	20776 KB	Output is correct
40	Correct	9 ms	20820 KB	Output is correct
41	Correct	12 ms	20820 KB	Output is correct
42	Correct	10 ms	20820 KB	Output is correct
43	Correct	10 ms	20776 KB	Output is correct
44	Correct	9 ms	20960 KB	Output is correct
45	Correct	12 ms	20852 KB	Output is correct
46	Correct	16 ms	20820 KB	Output is correct
47	Correct	163 ms	29892 KB	Output is correct
48	Correct	140 ms	29128 KB	Output is correct
49	Correct	163 ms	29828 KB	Output is correct
50	Correct	171 ms	31700 KB	Output is correct
51	Correct	232 ms	34604 KB	Output is correct
52	Correct	212 ms	34600 KB	Output is correct
53	Correct	56 ms	24512 KB	Output is correct
54	Correct	231 ms	31040 KB	Output is correct
55	Correct	203 ms	31644 KB	Output is correct
56	Correct	205 ms	31552 KB	Output is correct
57	Correct	222 ms	36864 KB	Output is correct
58	Correct	207 ms	31932 KB	Output is correct
59	Correct	277 ms	36412 KB	Output is correct
60	Correct	249 ms	36472 KB	Output is correct
61	Correct	240 ms	36612 KB	Output is correct
62	Correct	209 ms	34600 KB	Output is correct
63	Correct	239 ms	36048 KB	Output is correct
64	Correct	232 ms	35860 KB	Output is correct
65	Correct	253 ms	36080 KB	Output is correct
66	Correct	9 ms	20816 KB	Output is correct
67	Correct	179 ms	31604 KB	Output is correct
68	Correct	192 ms	31616 KB	Output is correct
69	Correct	203 ms	31568 KB	Output is correct
70	Correct	193 ms	32324 KB	Output is correct
71	Correct	196 ms	32536 KB	Output is correct
72	Correct	189 ms	32716 KB	Output is correct
73	Correct	200 ms	36924 KB	Output is correct
74	Correct	201 ms	36944 KB	Output is correct
75	Correct	189 ms	31992 KB	Output is correct
76	Correct	202 ms	33860 KB	Output is correct
77	Correct	116 ms	31404 KB	Output is correct
78	Correct	9 ms	20756 KB	Output is correct
79	Correct	11 ms	20872 KB	Output is correct
80	Correct	9 ms	20820 KB	Output is correct
81	Correct	9 ms	20820 KB	Output is correct
82	Correct	9 ms	20876 KB	Output is correct
83	Correct	9 ms	20948 KB	Output is correct
84	Correct	9 ms	20952 KB	Output is correct
85	Correct	9 ms	20828 KB	Output is correct
86	Correct	49 ms	22636 KB	Output is correct
87	Correct	45 ms	22600 KB	Output is correct
88	Correct	45 ms	22904 KB	Output is correct
89	Correct	38 ms	22992 KB	Output is correct
90	Correct	44 ms	23036 KB	Output is correct
91	Correct	40 ms	23004 KB	Output is correct
92	Correct	44 ms	22668 KB	Output is correct
93	Correct	153 ms	30016 KB	Output is correct
94	Correct	140 ms	29088 KB	Output is correct
95	Correct	146 ms	29744 KB	Output is correct
96	Correct	163 ms	31564 KB	Output is correct
97	Correct	217 ms	34680 KB	Output is correct
98	Correct	209 ms	34528 KB	Output is correct
99	Correct	54 ms	24516 KB	Output is correct
100	Correct	252 ms	36544 KB	Output is correct
101	Correct	240 ms	36416 KB	Output is correct
102	Correct	231 ms	36604 KB	Output is correct
103	Correct	245 ms	36112 KB	Output is correct
104	Correct	238 ms	35916 KB	Output is correct
105	Correct	238 ms	36032 KB	Output is correct
106	Correct	184 ms	30036 KB	Output is correct
107	Correct	206 ms	31076 KB	Output is correct
108	Correct	179 ms	31740 KB	Output is correct
109	Correct	180 ms	31700 KB	Output is correct
110	Correct	241 ms	36292 KB	Output is correct
111	Correct	250 ms	36548 KB	Output is correct