Submission #259949

#	Time	Username	Problem	Language	Result	Execution time	Memory
259949		pedroslrey	Global Warming (CEOI18_glo)	C++17	100 / 100	85 ms	3596 KiB

glo

#include <bits/stdc++.h>

using namespace std;
 
const int MAXN = 2e5 + 10;
const int INF = 2e9;

int xs[MAXN];
int dp_lis[MAXN];
int dp_lds[MAXN];
int pos[MAXN];
 
int main() {
	int n, x;
	scanf("%d %d", &n, &x);

	for (int i = 1; i <= n; ++i)
		scanf("%d", &xs[i]);
	
	for (int i = 1; i <= n; ++i)
		dp_lis[i] = INF;

	int ans = 0;
	for (int i = 1; i <= n; ++i) {
		int p = lower_bound(dp_lis, dp_lis + n + 1, xs[i]) - dp_lis;
		
		dp_lis[p] = xs[i];
		ans = max(ans, p);
		pos[i] = p;
	}

	for(int i = 1; i <= n; ++i)
		dp_lds[i] = INF;

	dp_lds[0] = -INF;
	for (int i = n; i >= 1; --i) {
		int idx = lower_bound(dp_lds, dp_lds + n + 1, -xs[i]) - dp_lds - 1;
		int p = lower_bound(dp_lds, dp_lds + n + 1, -xs[i] - x) - dp_lds;
		
		dp_lds[p] = -xs[i] - x;
		ans = max(ans, pos[i] + idx);
	}
	printf("%d\n", ans);
}

Compilation message (stderr)

glo.cpp: In function 'int main()':
glo.cpp:15:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d %d", &n, &x);
  ~~~~~^~~~~~~~~~~~~~~~~
glo.cpp:18:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d", &xs[i]);
   ~~~~~^~~~~~~~~~~~~~

• Subtask 1: 5 / 5
• Subtask 2: 10 / 10
• Subtask 3: 13 / 13
• Subtask 4: 10 / 10
• Subtask 5: 20 / 20
• Subtask 6: 17 / 17
• Subtask 7: 25 / 25