Submission #58913

#	Time	Username	Problem	Language	Result	Execution time	Memory
58913		reality	Ancient Books (IOI17_books)	C++17	70 / 100	280 ms	119180 KiB

books

#include "books.h"
#include "bits/stdc++.h"
using namespace std;
#define fi first
#define se second
#define ll long long
#define dbg(v) cerr<<#v<<" = "<<v<<'\n'
#define vi vector<int>
#define vl vector <ll>
#define pii pair<int,int>
#define mp make_pair
#define db long double
#define pb push_back
#define all(s) s.begin(),s.end()
template < class T > T smin(T &a,T b) {if (a > b) a = b;return a;}
template < class T > T smax(T &a,T b) {if (a < b) a = b;return a;}
#include "books.h"
const int oo = 1e9;
pii d[1024][1024];
int dp[1024][1024];
int mn[1024][1024];
int mx[1024][1024];
int n;
pii f1(int l,int r) {
	if (l > r)
		return mp(-1,-1);
	if (l == mn[l][r] && r == mx[l][r])
		return d[l][r] = mp(l,r);
	if (d[l][r] != mp(-1,-1))
		return d[l][r];
	return d[l][r] = f1(min(l,mn[l][r]),max(r,mx[l][r]));
}
int f(int l,int r) {
	if (l > r)
		return -1;
	if (l < 0 || r >= n)
		return oo;
	if (!l && r == n - 1)
		return dp[l][r] = 0;
	if (dp[l][r] != -1)
		return dp[l][r];
	int L,R;
	tie(L,R) = f1(l,r);
	if (mp(L,R) != mp(l,r))
		return dp[l][r] = f(L,R);
	if (0 <= l && r < n)
		return dp[l][r] = min(f(l - 1,r),f(l,r + 1)) + 2;
	else
		return oo;
}
long long minimum_walk(std::vector<int> p, int s) {
	n = p.size();
	while (!p.empty() && p.back() == n - 1)
			--n,p.pop_back();
	if (!n)
		return 0;
	ll ans = 0;
	for (int i = 0;i < n;++i)
		ans += abs(i - p[i]);
	if (!s && n > 1000) {
		int mx = 0;
		for (int i = 0;i + 1 < n;++i)
			smax(mx,p[i]),ans += 2 * (i == mx);	
	} else {
		memset(dp,-1,sizeof(dp));
		for (int i = 0;i < n;++i)
			for (int j = 0;j < n;++j)
				d[i][j] = mp(-1,-1);
		vi was(n,1);
		for (int i = 0;i < n;++i) {
			mn[i][i] = i;
			mx[i][i] = i;
			for (int j = i;j < n;++j) {
				if (j > i)
					mn[i][j] = mn[i][j - 1],
					mx[i][j] = mx[i][j - 1];
				smin(mn[i][j],p[j]);
				smax(mx[i][j],p[j]);
			}
		}
		ans += f(s,s);
	}
	return ans;
}

• Subtask 1: 12 / 12
• Subtask 2: 10 / 10
• Subtask 3: 28 / 28
• Subtask 4: 20 / 20
• Subtask 5: 0 / 30