Submission #975377

#	Time	Username	Problem	Language	Result	Execution time	Memory
975377		Syrius	Rainforest Jumps (APIO21_jumps)	C++14	100 / 100	1247 ms	54508 KiB

jumps

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

// #define int long long
#define ll long long
#define ff first
#define ss second
#define pint pair < int , int >
#define fast ios_base::sync_with_stdio(NULL); cin.tie(NULL)
typedef vector < int > vint;

const int inf = 1e9 + 9;
const int mxn = 2e5 + 5;
const int mod = 1e9 + 7;

int n;
int h[mxn] , le[mxn] , ri[mxn];
int inv[mxn];
int spx[19][mxn] , spn[19][mxn];

vint v;

struct node {

	int tl , tm , tr;
	int mx;
	node *left , *right;

	node (int l , int r) {
		tl = l , tr = r , tm = (l + r) / 2;
		mx = 0;
		left = right = NULL;
	}

	void build() {
		if (tl == tr) {
			mx = h[tl];
			return;
		}
		left = new node(tl , tm);
		right = new node(tm+1 , tr);
		left -> build();
		right -> build();
		mx = max(left -> mx , right -> mx);
	}

	pint query(int l , int r , int x) {
		if (tl == tr) {
			if (mx > x) return {-1 , 0};
			return {mx , 1};
		}
		if (tl == l && tr == r) {
			if (mx < x) return {mx , 1};
			pint pr = right -> query(tm+1 , r , x);
			if (pr.ss == 0) return pr;
			pint pl = left -> query(tl , tm , x);
			return {max(pl.ff , pr.ff) , 0};
		}
		if (r <= tm) return left -> query(l , r , x);
		if (l > tm) return right -> query(l , r , x);

		pint pr = right -> query(tm+1 , r , x);
		if (pr.ss == 0) return pr;
		pint pl = left -> query(l , tm , x);
		return {max(pl.ff , pr.ff) , pl.ss};
	}

	pint queryy(int l , int r , int x) {
		if (tl == tr) {
			if (mx < x) return {-1 , 0};
			return {mx , 1};
		}
		if (tl == l && tr == r) {
			if (mx < x) return {-1 , 0};
			pint pr = right -> queryy(tm+1 , tr , x);
			if (pr.ss == 1) return pr;
			return left -> queryy(tl , tm , x);
		}
		if (r <= tm) return left -> queryy(l , r , x);
		if (l > tm) return right -> queryy(l , r , x);

		pint pr = right -> queryy(tm+1 , r , x);
		if (pr.ss == 1) return pr;
		return left -> queryy(tl , tm , x);
	}
	

} *root;

void init(int N , vint H) {
	n = N;
	for (int i = 0; i < n; i++) {
		h[i] = H[i];
		inv[h[i]] = i;
	}

	root = new node(0 , n-1);
	root -> build();

	for (int i = 0; i < n; i++) {
		while (v.size() > 0 && v.back() < h[i]) {
			ri[v.back()] = h[i];
			v.pop_back();
		}
		if (v.size() > 0) le[h[i]] = v.back();
		v.push_back(h[i]);
	}

	for (int i = 0; i < n; i++) {
		spx[0][h[i]] = max(le[h[i]] , ri[h[i]]);
		spn[0][h[i]] = min(le[h[i]] , ri[h[i]]);
		if (spn[0][h[i]] == 0) spn[0][h[i]] = spx[0][h[i]];
	}

	for (int j = 1; j < 19; j++) {
		for (int i = 0; i < n; i++) {
			spx[j][h[i]] = spx[j-1][spx[j-1][h[i]]];
			spn[j][h[i]] = spn[j-1][spn[j-1][h[i]]];
		}
	}
}

int func(int a , int d) {
	if (h[a] > h[d]) return -1;
	int dis = 0;
	for (int i = 18; i >= 0; i--) {
		if (spx[i][h[a]] > h[d] || spx[i][h[a]] == 0) continue;
		if (spx[i][h[a]] == h[d]) return (1 << i);
		int t = func(inv[spx[i][h[a]]] , d);
		return (t == -1) ? t : ((1<<i) + t);
	}

	for (int i = 18; i >= 0; i--) {
		if (spn[i][h[a]] > h[d] || spn[i][h[a]] == 0) continue;
		if (spn[i][h[a]] == h[d]) return (1 << i);
		int t = func(inv[spn[i][h[a]]] , d);
		return (t == -1) ? t : ((1<<i) + t);
	}

	return -1;
}

int minimum_jumps(int a , int b , int c , int d) {

	int ans = inf;
	int hmax = root -> query(a , c-1 , inf).ff;

	int h2 = root -> query(c , d , inf).ff;
	int h1 = root -> query(a , b , h2).ff;
	if (h1 == -1) return -1;

	int hbef = -1;
	if (a > 0) hbef = root -> queryy(0 , a-1 , hmax).ff;
	if (hbef != -1 && hbef < h2) ans = min(ans , 1 + func(inv[h1] , inv[hbef]));

	int hmid = -1;
	if (b + 1 != c) hmid = root -> query(b+1 , c-1 , inf).ff;
	else return 1;
	
	if (hmid > h2) return -1;
	if (h1 > hmid) return 1;

	if (hmid != -1) ans = min(ans , 1 + func(inv[h1] , inv[hmid]));
	return (ans == inf) ? -1 : ans;
}

Compilation message (stderr)

jumps.cpp: In function 'int func(int, int)':
jumps.cpp:126:6: warning: unused variable 'dis' [-Wunused-variable]
  126 |  int dis = 0;
      |      ^~~

• Subtask 1: 4 / 4
• Subtask 2: 8 / 8
• Subtask 3: 13 / 13
• Subtask 4: 12 / 12
• Subtask 5: 23 / 23
• Subtask 6: 21 / 21
• Subtask 7: 19 / 19