Submission #309603

#	Time	Username	Problem	Language	Result	Execution time	Memory
309603		luciocf	Abduction 2 (JOI17_abduction2)	C++14	44 / 100	80 ms	25848 KiB

abduction2

#include <bits/stdc++.h>

using namespace std;

const int maxn = 5e4+10;
const int maxl = 17;

int n, m;
int a[2][maxn];

map<int, int> dp[maxn][2];

struct SparseTable
{
	int tab[2][2][maxn][maxl];

	void build(void)
	{
		for (int i = 1; i <= n; i++)
		{
			if (i > 1) tab[0][0][i][0] = a[0][i-1];

			if (i < n) tab[0][1][i][0] = a[0][i+1];
		}

		for (int i = 1; i <= m; i++)
		{
			if (i > 1) tab[1][0][i][0] = a[1][i-1];

			if (i < m) tab[1][1][i][0] = a[1][i+1];
		}

		for (int j = 1; j < maxl; j++)
		{
			for (int i = 1; i <= n; i++)
			{
				if (i-(1<<j) > 0)
					tab[0][0][i][j] = max(tab[0][0][i][j-1], tab[0][0][i-(1<<(j-1))][j-1]);

				if (i+(1<<j) <= n)
					tab[0][1][i][j] = max(tab[0][1][i][j-1], tab[0][1][i+(1<<(j-1))][j-1]);
			}

			for (int i = 1; i <= m; i++)
			{
				if (i-(1<<j) > 0)
					tab[1][0][i][j] = max(tab[1][0][i][j-1], tab[1][0][i-(1<<(j-1))][j-1]);

				if (i+(1<<j) <= m)
					tab[1][1][i][j] = max(tab[1][1][i][j-1], tab[1][1][i+(1<<(j-1))][j-1]);
			}
		}
	}

	int get_l(int pos, int x, int q)
	{
		for (int i = maxl-1; i >= 0; i--)
			if (pos-(1<<i) > 0 && tab[q][0][pos][i] < x)
				pos -= (1<<i);

		return pos-1;
	}

	int get_r(int pos, int x, int q)
	{
		for (int i = maxl-1; i >= 0; i--)
			if (pos+(1<<i) <= (!q ? n : m) && tab[q][1][pos][i] < x)
				pos += (1<<i);

		return pos+1;
	}
} ST;

int solve(int i, int j, int q)
{
	if (dp[i][q].find(j) != dp[i][q].end()) return dp[i][q][j];

	int ans;

	if (!q)
	{
		int l = ST.get_l(j, a[0][i], 1), r = ST.get_r(j, a[0][i], 1);

		if (l == 0 && r == m+1) ans = max(j-1, m-j);
		else if (l == 0) ans = (r-j + solve(i, r, 1));
		else if (r == m+1) ans = (j-l + solve(i, l, 1));
		else ans = max(r-j + solve(i, r, 1), j-l + solve(i, l, 1));
	}
	else
	{
		int l = ST.get_l(i, a[1][j], 0), r = ST.get_r(i, a[1][j], 0);

		if (l == 0 && r == n+1) ans = max(i-1, n-i);
		else if (l == 0) ans = (r-i + solve(r, j, 0));
		else if (r == n+1) ans =  (i-l + solve(l, j, 0));
		else ans = max(r-i + solve(r, j, 0), i-l + solve(l, j, 0));
	}

	return dp[i][q][j] = ans;
}

int main(void)
{
	int q;
	scanf("%d %d %d", &n, &m, &q);

	for (int i = 1; i <= n; i++)
		scanf("%d", &a[0][i]);

	for (int i = 1; i <= m; i++)
		scanf("%d", &a[1][i]);

	ST.build();

	while (q--)
	{
		int i, j;
		scanf("%d %d", &i, &j);

		printf("%d\n", max(solve(i, j, 0), solve(i, j, 1)));
	}
}

Compilation message (stderr)

abduction2.cpp: In function 'int main()':
abduction2.cpp:105:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  105 |  scanf("%d %d %d", &n, &m, &q);
      |  ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
abduction2.cpp:108:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  108 |   scanf("%d", &a[0][i]);
      |   ~~~~~^~~~~~~~~~~~~~~~
abduction2.cpp:111:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  111 |   scanf("%d", &a[1][i]);
      |   ~~~~~^~~~~~~~~~~~~~~~
abduction2.cpp:118:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  118 |   scanf("%d %d", &i, &j);
      |   ~~~~~^~~~~~~~~~~~~~~~~

• Subtask 1: 13 / 13
• Subtask 2: 10 / 10
• Subtask 3: 17 / 17
• Subtask 4: 4 / 4
• Subtask 5: 0 / 56