Submission #200191

#	Time	Username	Problem	Language	Result	Execution time	Memory
200191		wilwxk	Safety (NOI18_safety)	C++14	13 / 100	48 ms	19960 KiB

safety

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;

const int MAXN = 5e3+5;
int v[MAXN];
ll dp[MAXN][MAXN];
deque<pair<ll, int> > dq;
int n, x;

void update(ll val, int id, int l) {
	if(id > MAXN) return;
	// printf("upd %lld %d %d %d\n", val, id, l, r);
	while(dq.size() && dq.back().second < l) dq.pop_back();
	while(dq.size() && dq.front().first >= val) dq.pop_front();
	dq.push_front({val, id});
}

ll query() {
	return dq.back().first;
}

int main() {
	scanf("%d %d", &n, &x);
	for(int i = 1; i <= n; i++) scanf("%d", &v[i]);

	for(int i = 1; i <= n; i++) {
		for(int j = 0; j < min(x, MAXN); j++) update(dp[i-1][j], j, -1);

		for(int j = 0; j < MAXN; j++) {
			update(dp[i-1][j+x], j+x, j-x);

			ll cost = abs(j-v[i]);
			cost += query();
			dp[i][j] = cost;
			// printf("%d %d >> %lld\n", i, j, cost);
		}
		while(dq.size()) dq.pop_back();
	}

	ll ans = 1e18;
	for(int i = 0; i < MAXN; i++) ans = min(ans, dp[n][i]);
	printf("%lld\n", ans);
}

Compilation message (stderr)

safety.cpp: In function 'int main()':
safety.cpp:24:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d %d", &n, &x);
  ~~~~~^~~~~~~~~~~~~~~~~
safety.cpp:25:35: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  for(int i = 1; i <= n; i++) scanf("%d", &v[i]);
                              ~~~~~^~~~~~~~~~~~~

• Subtask 1: 3 / 3
• Subtask 2: 4 / 4
• Subtask 3: 0 / 9
• Subtask 4: 0 / 5
• Subtask 5: 6 / 6
• Subtask 6: 0 / 11
• Subtask 7: 0 / 11
• Subtask 8: 0 / 22
• Subtask 9: 0 / 29