Submission #915130

#	Time	Username	Problem	Language	Result	Execution time	Memory
915130		OAleksa	Xylophone (JOI18_xylophone)	C++14	100 / 100	33 ms	1212 KiB

xylophone

#include "xylophone.h"
#include<bits/stdc++.h>
using namespace std;
const int MAXN = 5069;
int ans[MAXN], vis[MAXN];
void solve(int N) {
  int n = N;
	int l = 2, r = n, mx = 2;
	while (l <= r) {
    int mid = (l + r) / 2;
    if (query(1, mid) == n - 1) {
      mx = mid;
      r = mid - 1;
    }
    else
      l = mid + 1;
	}
	ans[mx] = n;
	vis[n] = 1;
	if (mx < n) {
    int x = query(mx, mx + 1);
    ans[mx + 1] = n - x;
    vis[n - x] = 1;
	}
  int x = query(mx - 1, mx);
  ans[mx - 1] = n - x;
  vis[n - x] = 1;
  for (int i = mx - 2;i >= 1;i--) {
    int x = query(i, i + 1);
    int v1 = ans[i + 1] - x;
    int v2 = ans[i + 1] + x;
    if (v1 < 1 || vis[v1])
      ans[i] = v2;
    else if (v2 > n || vis[v2])
      ans[i] = v1;
    else {
      int y = query(i, i + 2);
      if (y == abs(ans[i + 2] - ans[i + 1]) || y == x) {
        if (ans[i + 2] > ans[i + 1])
          ans[i] = v2;
        else
          ans[i] = v1;
      }
      else {
         if (ans[i + 2] > ans[i + 1])
          ans[i] = v1;
        else
          ans[i] = v2;
      }
    }
    vis[ans[i]] = 1;
  }
  for (int i = mx + 2;i <= n;i++) {
    int x = query(i - 1, i);
    int v1 = ans[i - 1] - x;
    int v2 = ans[i - 1] + x;
    if (v1 < 1 || vis[v1])
      ans[i] = v2;
    else if (v2 > n || vis[v2])
      ans[i] = v1;
    else {
      int y = query(i - 2, i);
      if (y == abs(ans[i - 2] - ans[i - 1]) || y == x) {
        if (ans[i - 2] > ans[i - 1])
          ans[i] = v2;
        else
          ans[i] = v1;
      }
      else {
        if (ans[i - 2] > ans[i - 1])
          ans[i] = v1;
        else
          ans[i] = v2;
      }
    }
    vis[ans[i]] = 1;
  }
	for(int i = 1; i <= n; i++) {
		answer(i, ans[i]);
	}
}

• Subtask 1: 11 / 11
• Subtask 2: 36 / 36
• Subtask 3: 53 / 53