oj.uz

Submission #103743

# Submission time Handle Problem Language Result Execution time Memory
103743 2019-04-02T11:55:22 Z igba Watching (JOI13_watching) C++17
100 / 100
 246 ms 16396 KB 
#include <bits/stdc++.h>
 
using namespace std;
const int MAXN = 2020, INF = 0x3f3f3f3f;
int n, p, q, a[MAXN], precalc[MAXN][2], dp[MAXN][MAXN];
 
bool ok(int w)
{
	for(int i = 1, j = 1; i <= n; ++i, j = i)
	{
		while(a[j] - a[i] < w && j <= n)
			j++;
		precalc[i][0] = j;
		while(a[j] - a[i] < 2 * w && j <= n)
			j++;
		precalc[i][1] = j;
	}
	precalc[n + 1][0] = precalc[n + 1][1] = n + 1;
	memset(dp, 0, sizeof dp);
	dp[0][0] = 1;
	for(int i = 0; i <= p; ++i)
		for(int j = 0; j <= q; ++j)
		{
			if(i >= 1)
				dp[i][j] = max(dp[i][j], precalc[dp[i - 1][j]][0]);
			if(j >= 1)
				dp[i][j] = max(dp[i][j], precalc[dp[i][j - 1]][1]);
		}
	return dp[p][q] > n;
}
 
int main()
{
	scanf("%d %d %d", &n, &p, &q);
	for(int i = 1; i <= n; ++i)
		scanf("%d", &a[i]);
	sort(a + 1, a + n + 1);
	if(p + q >= n)
		printf("1\n"), exit(0);
	int beg = 1, end = 1e9, mid;
	while(beg < end)
	{
		mid = (beg + end) >> 1;
		if(ok(mid))
			end = mid;
		else
			beg = mid + 1;
	}
	printf("%d\n", end);
}

Compilation message

watching.cpp: In function 'int main()':
watching.cpp:34:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d %d %d", &n, &p, &q);
  ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
watching.cpp:36:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d", &a[i]);
   ~~~~~^~~~~~~~~~~~~

Subtask #1
50.0 / 50.0

# Verdict Execution time Memory Grader output
1 Correct 102 ms 16376 KB Output is correct
2 Correct 2 ms 256 KB Output is correct
3 Correct 124 ms 16368 KB Output is correct
4 Correct 2 ms 384 KB Output is correct
5 Correct 2 ms 384 KB Output is correct
6 Correct 2 ms 384 KB Output is correct
7 Correct 82 ms 16256 KB Output is correct
8 Correct 103 ms 16248 KB Output is correct
9 Correct 98 ms 16256 KB Output is correct
10 Correct 97 ms 16256 KB Output is correct
11 Correct 110 ms 16332 KB Output is correct
12 Correct 109 ms 16384 KB Output is correct
13 Correct 102 ms 16256 KB Output is correct
14 Correct 97 ms 16328 KB Output is correct
15 Correct 113 ms 16376 KB Output is correct

Subtask #2
50.0 / 50.0

# Verdict Execution time Memory Grader output
1 Correct 162 ms 16256 KB Output is correct
2 Correct 2 ms 384 KB Output is correct
3 Correct 2 ms 384 KB Output is correct
4 Correct 2 ms 384 KB Output is correct
5 Correct 2 ms 256 KB Output is correct
6 Correct 2 ms 256 KB Output is correct
7 Correct 101 ms 16284 KB Output is correct
8 Correct 133 ms 16384 KB Output is correct
9 Correct 152 ms 16384 KB Output is correct
10 Correct 146 ms 16396 KB Output is correct
11 Correct 130 ms 16256 KB Output is correct
12 Correct 246 ms 16376 KB Output is correct
13 Correct 100 ms 16376 KB Output is correct
14 Correct 123 ms 16352 KB Output is correct
15 Correct 108 ms 16384 KB Output is correct