Submission #765820

#	Time	Username	Problem	Language	Result	Execution time	Memory
765820		SanguineChameleon	Shortcut (IOI16_shortcut)	C++17	38 / 100	2092 ms	245564 KiB

shortcut

#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")

#include "shortcut.h"
#include <bits/stdc++.h>
using namespace std;

const int maxn = 3e3 + 20;
const long long inf = 1e18L;
long long len[maxn];
bool bad1[maxn];
bool bad2[maxn];
long long max3[maxn][maxn];
long long max4[maxn][maxn];
long long max5[maxn][maxn];
long long max6[maxn][maxn];
int depth[maxn];
int n, c;

long long calc(long long lim) {
	for (int j = 1; j <= n; j++) {
		bad1[j] = (j > 1 ? bad1[j - 1] : false);
		for (int i = 1; i < j; i++) {
			if (len[j] - len[i] + depth[i] + depth[j] > lim) {
				bad1[j] = true;
				break;
			}
		}
	}
	for (int i = n; i >= 1; i--) {
		bad2[i] = (i < n ? bad2[i + 1] : false);
		for (int j = i + 1; j <= n; j++) {
			if (len[j] - len[i] + depth[i] + depth[j] > lim) {
				bad2[i] = true;
				break;
			}
		}
	}
	for (int j = 1; j <= n; j++) {
		for (int i = 1; i < j; i++) {
			max3[i][j] = (i > 1 ? max3[i - 1][j] : -inf);
			long long d1 = - len[i] - len[j] + c + depth[i] + depth[j];
			long long d2 = len[j] - len[i] + depth[i] + depth[j];
			if (d2 > lim) {
				max3[i][j] = max(max3[i][j], d1);
			}
		}
	}
	for (int i = 1; i <= n; i++) {
		for (int j = i + 2; j <= n; j++) {
			max3[i][j] = max(max3[i][j], max3[i][j - 1]);
		}
	}
	for (int i = 1; i <= n; i++) {
		for (int j = n; j > i; j--) {
			max4[i][j] = (j < n ? max4[i][j + 1] : -inf);
			long long d1 = len[i] + len[j] + c + depth[i] + depth[j];
			long long d2 = len[j] - len[i] + depth[i] + depth[j];
			if (d2 > lim) {
				max4[i][j] = max(max4[i][j], d1);
			}
		}
	}
	for (int j = 1; j <= n; j++) {
		for (int i = j - 2; i >= 1; i--) {
			max4[i][j] = max(max4[i][j], max4[i + 1][j]);
		}
	}
	for (int j = 1; j <= n; j++) {
		for (int i = j - 1; i >= 1; i--) {
			max5[i][j] = (i + 1 < j ? max(max5[i + 1][j], max5[i][j - 1]) : -inf);
			long long d1 = len[i] - len[j] + c + depth[i] + depth[j];
			long long d2 = len[j] - len[i] + depth[i] + depth[j];
			if (d2 > lim) {
				max5[i][j] = max(max5[i][j], d1);
			}
		}
	}
	for (int j = n; j >= 1; j--) {
		for (int i = 1; i <= n; i++) {
			max6[i][j] = max((i > 1 ? max6[i - 1][j] : -inf), (j < n ? max6[i][j + 1] : -inf));
			long long d1 = len[j] - len[i] + c + depth[i] + depth[j];
			long long d2 = len[j] - len[i] + depth[i] + depth[j];
			if (d2 > lim) {
				max6[i][j] = max(max6[i][j], d1);
			}
		}
	}
	long long res = inf;
	for (int x = 1; x <= n; x++) {
		if (bad1[x]) {
			continue;
		}
		for (int y = x + 1; y <= n; y++) {
			if (bad2[y]) {
				continue;
			}
			long long mx = 0;
			mx = max(mx, max3[x][y] + (len[x] + len[y]));
			mx = max(mx, max4[x][y] - (len[x] + len[y]));
			mx = max(mx, max5[x][y] + (len[y] - len[x]));
			mx = max(mx, max6[x][y] - (len[y] - len[x]));
			res = min(res, mx);
		}
	}
	return res;
}

long long dist[maxn * maxn];

long long find_shortcut(int _n, vector<int> _len, vector<int> _depth, int _c) {
	n = _n;
	c = _c;
	len[1] = 0;
	for (int i = 2; i <= n; i++) {
		len[i] = len[i - 1] + _len[i - 2];
	}
	for (int i = 1; i <= n; i++) {
		depth[i] = _depth[i - 1];
	}
	int mx1 = 0;
	int mx2 = 0;
	for (int i = 1; i <= n; i++) {
		if (depth[i] > depth[mx1]) {
			mx2 = mx1;
			mx1 = i;
		}
		else if (depth[i] > depth[mx2]) {
			mx2 = i;
		}
	}
	int cnt = 0;
	for (int i = 1; i <= n; i++) {
		for (int j = i + 1; j <= n; j++) {
			dist[cnt++] = len[j] - len[i] + depth[i] + depth[j];
		}
	}
	sort(dist, dist + cnt, greater<>());
	while (dist[cnt - 1] <= depth[mx1] + depth[mx2]) {
		cnt--;
	}
	long long res = dist[0];
	int lt = 0;
	int rt = cnt - 1;
	while (lt <= rt) {
		int mt = (lt + rt) / 2;
		long long mx = calc(dist[mt] - 1);
		if (mx < dist[mt]) {
			res = max(mx, dist[mt + 1]);
			lt = mt + 1;
		}
		else {
			rt = mt - 1;
		}
	}
	return res;
}

• 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