Submission #464906

#	Submission time	Handle	Problem	Language	Result	Execution time	Memory
464906	2021-08-14T12:16:19 Z	blue	Ancient Books (IOI17_books)	C++17	50 / 100	195 ms	24036 KB

books

#include "books.h"
#include <vector>
#include <cstdlib>
#include <algorithm>
#include <iostream>
using namespace std;

const int maxN = 1'000'000;

const int ind_R = 1'000'005;
const int ind_L = -1;

const long long INF = 1'000'000'000'000'000'000LL;

int N;
vector<int> P;

int S;

int cycle_ind = -1;
vector<int> cycle(maxN, -1);
vector<int> L(maxN, ind_R);
vector<int> R(maxN, ind_L);

long long essential_cost = 0;

void extend(int& l, int& r) //[l, r] is extended fully except for the cycles of l and r
{
	int l_new = min(L[cycle[l]], L[cycle[r]]);
	int r_new = max(R[cycle[l]], R[cycle[r]]);

	// cerr << "ln = " << l_new << ", rn = " << r_new << '\n';

	while(l_new <= l-1 || r+1 <= r_new)
	{
		if(l_new <= l-1)
		{
			l--;
			l_new = min(l_new, L[cycle[l]]);
			r_new = max(r_new, R[cycle[l]]);
		}

		if(r+1 <= r_new)
		{
			r++;
			l_new = min(l_new, L[cycle[r]]);
			r_new = max(r_new, R[cycle[r]]);
		}
	}
}

long long minimum_walk(vector<int> p, int s)
{
	N = p.size();
	P = p;
	S = s;

	int solve_L = S;
	int solve_R = S;

	for(int i = 0; i < N; i++)
	{
		essential_cost += abs(P[i] - i);

		if(P[i] != i)
		{
			solve_L = min(solve_L, i);
			solve_R = max(solve_R, i);
		}

		if(cycle[i] != -1) continue;

		cycle_ind++;

		int j = i;
		do
		{
			cycle[j] = cycle_ind;

			L[ cycle[j] ] = min(L[ cycle[j] ], j);
			R[ cycle[j] ] = max(R[ cycle[j] ], j);

			j = P[j];
		} while(j != i);
	}

	if(solve_L == S && solve_R == S) return 0;

	// for(int i = 0; i < N; i++) cerr << cycle[i] << ' ';
	// cerr << '\n';
	//
	// cerr << "solve range = " <<  solve_L << ' ' << solve_R << '\n';


	long long extra_cost = 0;

	int l = S;
	int r = S;
	// cerr << "l = " << l << ", r = " << r << '\n';
	extend(l, r);
	// cerr << "l = " << l << ", r = " << r << '\n';

	while(l != solve_L || r != solve_R)
	{
		extend(l, r);

		int new_l = -1, new_r = -1;
		int left_cost, right_cost;
		for(int i = l-1; i >= solve_L; i--)
		{
			if(P[i] != i)
			{
				new_l = i;
				left_cost = 2*(l - new_l);
				break;
			}
		}
		for(int i = r+1; i <= solve_R; i++)
		{
			if(P[i] != i)
			{
				new_r = i;
				right_cost = 2*(new_r - r);
				break;
			}
		}

		if(new_l != -1 && new_r != -1)
		{
			extend(new_l, new_r);

			// if((S <= R[ cycle[new_l] ]) != (L[ cycle[new_r] ] <= S))
			// 	while(1);


			if(S <= R[ cycle[new_l] ]) //&& L[ cycle[new_r] ] <= S
			{
				extra_cost += min(2*(new_r - r), 2*(l - new_l));
			}
			else
			{
				extra_cost += 2*(new_r - r) + 2*(l - new_l);
			}

			l = new_l;
			r = new_r;
			extend(l, r);
		}
		else if(new_l != -1)
		{
			extra_cost += 2*(l - new_l);
			l = new_l;
			extend(l, r);
		}
		else if(new_r != -1)
		{
			extra_cost += 2*(new_r - r);
			r = new_r;
			extend(l, r);
		}
		else break;
	}

	return essential_cost + extra_cost;
}

Compilation message

books.cpp: In function 'long long int minimum_walk(std::vector<int>, int)':
books.cpp:108:7: warning: variable 'left_cost' set but not used [-Wunused-but-set-variable]
  108 |   int left_cost, right_cost;
      |       ^~~~~~~~~
books.cpp:108:18: warning: variable 'right_cost' set but not used [-Wunused-but-set-variable]
  108 |   int left_cost, right_cost;
      |                  ^~~~~~~~~~

Subtask #1

12.0 / 12.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	6 ms	11980 KB	Output is correct
2	Correct	7 ms	12052 KB	Output is correct
3	Correct	6 ms	11980 KB	Output is correct
4	Correct	9 ms	12040 KB	Output is correct
5	Correct	7 ms	11980 KB	Output is correct
6	Correct	6 ms	12048 KB	Output is correct
7	Correct	7 ms	12052 KB	Output is correct
8	Correct	7 ms	11968 KB	Output is correct
9	Correct	7 ms	11932 KB	Output is correct
10	Correct	7 ms	11980 KB	Output is correct
11	Correct	7 ms	11992 KB	Output is correct
12	Correct	6 ms	11980 KB	Output is correct
13	Correct	7 ms	12056 KB	Output is correct
14	Correct	7 ms	12016 KB	Output is correct
15	Correct	6 ms	11980 KB	Output is correct
16	Correct	6 ms	12044 KB	Output is correct
17	Correct	8 ms	11944 KB	Output is correct
18	Correct	7 ms	11980 KB	Output is correct

Subtask #2

10.0 / 10.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	6 ms	11980 KB	Output is correct
2	Correct	7 ms	12052 KB	Output is correct
3	Correct	6 ms	11980 KB	Output is correct
4	Correct	9 ms	12040 KB	Output is correct
5	Correct	7 ms	11980 KB	Output is correct
6	Correct	6 ms	12048 KB	Output is correct
7	Correct	7 ms	12052 KB	Output is correct
8	Correct	7 ms	11968 KB	Output is correct
9	Correct	7 ms	11932 KB	Output is correct
10	Correct	7 ms	11980 KB	Output is correct
11	Correct	7 ms	11992 KB	Output is correct
12	Correct	6 ms	11980 KB	Output is correct
13	Correct	7 ms	12056 KB	Output is correct
14	Correct	7 ms	12016 KB	Output is correct
15	Correct	6 ms	11980 KB	Output is correct
16	Correct	6 ms	12044 KB	Output is correct
17	Correct	8 ms	11944 KB	Output is correct
18	Correct	7 ms	11980 KB	Output is correct
19	Correct	7 ms	12012 KB	Output is correct
20	Correct	7 ms	11944 KB	Output is correct
21	Correct	7 ms	11980 KB	Output is correct
22	Correct	6 ms	12052 KB	Output is correct
23	Correct	6 ms	11980 KB	Output is correct
24	Correct	7 ms	11980 KB	Output is correct
25	Correct	7 ms	11980 KB	Output is correct
26	Correct	10 ms	11980 KB	Output is correct
27	Correct	7 ms	12064 KB	Output is correct
28	Correct	7 ms	12052 KB	Output is correct
29	Correct	7 ms	12056 KB	Output is correct

Subtask #3

28.0 / 28.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	6 ms	11980 KB	Output is correct
2	Correct	7 ms	12052 KB	Output is correct
3	Correct	6 ms	11980 KB	Output is correct
4	Correct	9 ms	12040 KB	Output is correct
5	Correct	7 ms	11980 KB	Output is correct
6	Correct	6 ms	12048 KB	Output is correct
7	Correct	7 ms	12052 KB	Output is correct
8	Correct	7 ms	11968 KB	Output is correct
9	Correct	7 ms	11932 KB	Output is correct
10	Correct	7 ms	11980 KB	Output is correct
11	Correct	7 ms	11992 KB	Output is correct
12	Correct	6 ms	11980 KB	Output is correct
13	Correct	7 ms	12056 KB	Output is correct
14	Correct	7 ms	12016 KB	Output is correct
15	Correct	6 ms	11980 KB	Output is correct
16	Correct	6 ms	12044 KB	Output is correct
17	Correct	8 ms	11944 KB	Output is correct
18	Correct	7 ms	11980 KB	Output is correct
19	Correct	7 ms	12012 KB	Output is correct
20	Correct	7 ms	11944 KB	Output is correct
21	Correct	7 ms	11980 KB	Output is correct
22	Correct	6 ms	12052 KB	Output is correct
23	Correct	6 ms	11980 KB	Output is correct
24	Correct	7 ms	11980 KB	Output is correct
25	Correct	7 ms	11980 KB	Output is correct
26	Correct	10 ms	11980 KB	Output is correct
27	Correct	7 ms	12064 KB	Output is correct
28	Correct	7 ms	12052 KB	Output is correct
29	Correct	7 ms	12056 KB	Output is correct
30	Correct	195 ms	24028 KB	Output is correct
31	Correct	183 ms	24004 KB	Output is correct
32	Correct	138 ms	24020 KB	Output is correct
33	Correct	143 ms	24012 KB	Output is correct
34	Correct	148 ms	24000 KB	Output is correct
35	Correct	145 ms	24004 KB	Output is correct
36	Correct	142 ms	24012 KB	Output is correct
37	Correct	139 ms	24008 KB	Output is correct
38	Correct	144 ms	24016 KB	Output is correct
39	Correct	157 ms	24004 KB	Output is correct
40	Correct	143 ms	24020 KB	Output is correct
41	Correct	158 ms	24004 KB	Output is correct
42	Correct	160 ms	24036 KB	Output is correct
43	Correct	140 ms	24004 KB	Output is correct

Subtask #4

0 / 20.0

#	Verdict	Execution time	Memory	Grader output
1	Incorrect	9 ms	11980 KB	3rd lines differ - on the 1st token, expected: '3304', found: '4612'
2	Halted	0 ms	0 KB	-

Subtask #5

0 / 30.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	6 ms	11980 KB	Output is correct
2	Correct	7 ms	12052 KB	Output is correct
3	Correct	6 ms	11980 KB	Output is correct
4	Correct	9 ms	12040 KB	Output is correct
5	Correct	7 ms	11980 KB	Output is correct
6	Correct	6 ms	12048 KB	Output is correct
7	Correct	7 ms	12052 KB	Output is correct
8	Correct	7 ms	11968 KB	Output is correct
9	Correct	7 ms	11932 KB	Output is correct
10	Correct	7 ms	11980 KB	Output is correct
11	Correct	7 ms	11992 KB	Output is correct
12	Correct	6 ms	11980 KB	Output is correct
13	Correct	7 ms	12056 KB	Output is correct
14	Correct	7 ms	12016 KB	Output is correct
15	Correct	6 ms	11980 KB	Output is correct
16	Correct	6 ms	12044 KB	Output is correct
17	Correct	8 ms	11944 KB	Output is correct
18	Correct	7 ms	11980 KB	Output is correct
19	Correct	7 ms	12012 KB	Output is correct
20	Correct	7 ms	11944 KB	Output is correct
21	Correct	7 ms	11980 KB	Output is correct
22	Correct	6 ms	12052 KB	Output is correct
23	Correct	6 ms	11980 KB	Output is correct
24	Correct	7 ms	11980 KB	Output is correct
25	Correct	7 ms	11980 KB	Output is correct
26	Correct	10 ms	11980 KB	Output is correct
27	Correct	7 ms	12064 KB	Output is correct
28	Correct	7 ms	12052 KB	Output is correct
29	Correct	7 ms	12056 KB	Output is correct
30	Correct	195 ms	24028 KB	Output is correct
31	Correct	183 ms	24004 KB	Output is correct
32	Correct	138 ms	24020 KB	Output is correct
33	Correct	143 ms	24012 KB	Output is correct
34	Correct	148 ms	24000 KB	Output is correct
35	Correct	145 ms	24004 KB	Output is correct
36	Correct	142 ms	24012 KB	Output is correct
37	Correct	139 ms	24008 KB	Output is correct
38	Correct	144 ms	24016 KB	Output is correct
39	Correct	157 ms	24004 KB	Output is correct
40	Correct	143 ms	24020 KB	Output is correct
41	Correct	158 ms	24004 KB	Output is correct
42	Correct	160 ms	24036 KB	Output is correct
43	Correct	140 ms	24004 KB	Output is correct
44	Incorrect	9 ms	11980 KB	3rd lines differ - on the 1st token, expected: '3304', found: '4612'
45	Halted	0 ms	0 KB	-