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Submission #100811

# Submission time Handle Problem Language Result Execution time Memory
100811 2019-03-14T15:22:52 Z arman_ferdous Watching (JOI13_watching) C++17
100 / 100
 187 ms 8576 KB 
#include <bits/stdc++.h>
using namespace std;

using ll = long long;
const int N = 2019;
int n, p, q, arr[N];

int x[N], y[N], dp[N][N];
bool can(int w) {
	int cur = 0;
	for(int i = 0; i < n; i++) {
		while(cur + 1 < n && arr[cur + 1] - arr[i] + 1 <= w) cur++;
		x[i] = cur;
	} cur = 0;
	for(int i = 0; i < n; i++) {
		while(cur + 1 < n && arr[cur + 1] - arr[i] + 1 <= 2*w) cur++;
		y[i] = cur;
	}
	for(int i = 0; i <= p; i++)
		for(int j = 0; j <= q; j++) {
			dp[i][j] = -1;
			if(i == 0 && j == 0) continue;
			if(i != 0) dp[i][j] = max({x[dp[i-1][j] + 1], dp[i-1][j], dp[i][j]});
			if(j != 0) dp[i][j] = max({y[dp[i][j-1] + 1], dp[i][j-1], dp[i][j]});
		}
	return dp[p][q] >= n-1;
}

int main() {
	scanf("%d %d %d", &n, &p, &q);
	for(int i = 0; i < n; i++)
		scanf("%d", &arr[i]);
	sort(arr,arr+n);
	if(p + q >= n) {
		puts("1");
		return 0;
	}
	int lo = 1, hi = (int)1e9+10, ans;
	while(lo <= hi) {
		int mid = (lo + hi) >> 1;
		if(can(mid)) hi = mid-1, ans = mid;
		else lo = mid+1;
	} printf("%d", ans);
	return 0;
}

Compilation message

watching.cpp: In function 'int main()':
watching.cpp:30:7: 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:32:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d", &arr[i]);
   ~~~~~^~~~~~~~~~~~~~~

Subtask #1
50.0 / 50.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 384 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 384 KB Output is correct
7 Correct 3 ms 360 KB Output is correct
8 Correct 2 ms 384 KB Output is correct
9 Correct 3 ms 384 KB Output is correct
10 Correct 3 ms 384 KB Output is correct
11 Correct 2 ms 512 KB Output is correct
12 Correct 4 ms 512 KB Output is correct
13 Correct 2 ms 384 KB Output is correct
14 Correct 2 ms 384 KB Output is correct
15 Correct 3 ms 384 KB Output is correct

Subtask #2
50.0 / 50.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 384 KB Output is correct
2 Correct 2 ms 384 KB Output is correct
3 Correct 2 ms 384 KB Output is correct
4 Correct 3 ms 384 KB Output is correct
5 Correct 2 ms 384 KB Output is correct
6 Correct 4 ms 384 KB Output is correct
7 Correct 3 ms 384 KB Output is correct
8 Correct 21 ms 1288 KB Output is correct
9 Correct 23 ms 3840 KB Output is correct
10 Correct 41 ms 8576 KB Output is correct
11 Correct 38 ms 1152 KB Output is correct
12 Correct 187 ms 8064 KB Output is correct
13 Correct 4 ms 356 KB Output is correct
14 Correct 3 ms 512 KB Output is correct
15 Correct 4 ms 512 KB Output is correct