Submission #958900

#	Time	Username	Problem	Language	Result	Execution time	Memory
958900		MinaRagy06	Shortcut (IOI16_shortcut)	C++17	38 / 100	2064 ms	342868 KiB

shortcut

#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
#include "shortcut.h"
#ifdef MINA
#include "grader.cpp"
#endif
using namespace std;
#define ll long long

const int N = 3005;
ll v1[N][N], v2[N][N], v3[N][N], v4[N][N], mn2[N][N], mn3[N][N];
ll find_shortcut(int n, vector<int> l, vector<int> a, int c) {
	reverse(l.begin(), l.end()), l.push_back(0), reverse(l.begin(), l.end()), l.push_back(0);
	reverse(a.begin(), a.end()), a.push_back(-1), reverse(a.begin(), a.end());
	ll prf[n + 2]{};
	for (int i = 2; i <= n; i++) {
		prf[i] = prf[i - 1] + l[i - 1];
	}
	ll prfmx[n + 2]{}, prfd[n + 2]{}, sufmx[n + 2]{}, sufd[n + 2]{};
	for (int i = 1; i <= n; i++) {
		prfmx[i] = max(prfmx[i - 1] + l[i - 1], (ll)a[i]);
		prfd[i] = max(prfd[i - 1], prfmx[i - 1] + l[i - 1] + a[i]);
	}
	for (int i = n; i >= 1; i--) {
		sufmx[i] = max(sufmx[i + 1] + l[i], (ll)a[i]);
		sufd[i] = max(sufd[i + 1], sufmx[i + 1] + l[i] + a[i]);
	}
	auto check = [&] (ll t) {
		for (int i = 1; i <= n; i++) {
			for (int j = i + 1; j <= n; j++) {
				if (prf[j] - prf[i] + a[i] + a[j] <= t) {
					v1[i][j] = v2[i][j] = v3[i][j] = v4[i][j] = 1e18;
					continue;
				}
				v1[i][j] = prf[j] - prf[i] - a[i] - a[j];
				v2[i][j] = - prf[j] + prf[i] - a[i] - a[j];
				v3[i][j] = prf[i] + prf[j] - a[i] - a[j];
				v4[i][j] = - prf[i] - prf[j] - a[i] - a[j];
			}
		}
		for (int x = 1; x <= n; x++) {
			for (int y = x + 1; y <= n; y++) {
				mn2[x][y] = mn3[x][y] = 1e18;
			}
		}
		for (int y = 2; y <= n; y++) {
			for (int i = 1; i < y; i++) {
				if (i - 1 >= 1) {
					v3[i][y] = min(v3[i][y], v3[i - 1][y]);
					v2[i][y] = min(v2[i][y], v2[i - 1][y]);
				}
			}
		}
		for (int x = 1; x <= n; x++) {
			for (int i = n; i >= 1; i--) {
				if (i + 1 <= n) {
					v4[x][i] = min(v4[x][i], v4[x][i + 1]);
				}
			}
			ll mn = 1e18, mn_ = 1e18;
			for (int y = x + 1; y <= n; y++) {
				mn_ = min(mn_, v3[x][y]);
				mn3[x][y] = mn_;
			}
			mn = mn_ = 1e18;
			for (int y = n; y >= x + 1; y--) {
				mn = min(mn, v2[x][y]);
				mn2[x][y] = mn;
			}
		}
		for (int y = 2; y <= n; y++) {
			ll mn1 = 1e18;
			ll mn4 = 1e18;
			for (int x = y - 1; x >= 1; x--) {
				v1[x][x + 1] = min(v1[x][x + 1], v1[x][y]);
				mn1 = min(mn1, v1[x][x + 1]);
				mn4 = min(mn4, v4[x][y]);
				ll len = prf[y] - prf[x] + c;
				if (prfd[x] <= t && sufd[y] <= t && len - mn1 <= t && -(prf[y] - prf[x]) + c - mn2[x][y] <= t && len + 2 * prf[x] - mn3[x][y] <= t && len - 2 * prf[y] - mn4 <= t) {
					return 1;
				}
			}
		}
		return 0;
	};
	ll s = 0, e = 1ll << 42;
	while (s <= e) {
		ll md = (s + e) >> 1;
		if (check(md)) {
			e = md - 1;
		} else {
			s = md + 1;
		}
	}
	return s;
}

• Subtask 1: 9 / 9
• Subtask 2: 14 / 14
• Subtask 3: 8 / 8
• Subtask 4: 7 / 7
• Subtask 5: 0 / 33
• Subtask 6: 0 / 22
• Subtask 7: 0 / 4
• Subtask 8: 0 / 3