Submission #972552

#	Time	Username	Problem	Language	Result	Execution time	Memory
972552		dubabuba	Rainforest Jumps (APIO21_jumps)	C++14	48 / 100	921 ms	104576 KiB

jumps

#include <bits/stdc++.h>
#include "jumps.h"

using namespace std;

template<typename T> void ono_min(T &MIN, T CMP) { if(MIN > CMP) MIN = CMP; }
template<typename T> void ono_max(T &MAX, T CMP) { if(MAX < CMP) MAX = CMP; }

typedef pair<int, int> pii;
#define ff first
#define ss second
#define MP make_pair

const int mxk = 32;
const int mxn = 2e5 + 10;
int L[mxn], h[mxn];
int R[mxn], n;

vector<int> adj[mxn];
int mx[mxk][mxn], mn[mxk][mxn];
pii ll[mxk][mxn], rr[mxk][mxn];

pii str[mxn * 4];
void build(int id, int tl, int tr) {
	if(tl == tr) {
		str[id] = MP(h[tl], tl);
		return;
	}
	int tm = (tl + tr) / 2;
	build(id * 2 + 1, tl, tm);
	build(id * 2 + 2, tm + 1, tr);
	str[id] = max(str[id * 2 + 1], str[id * 2 + 2]);
}

pii query(int id, int tl, int tr, int l, int r) {
	if(l > r) return MP(0, -1);
	if(tl == l && r == tr) return str[id];
	int tm = (tl + tr) / 2;
	if(r <= tm) return query(id * 2 + 1, tl, tm, l, r);
	if(tm < l) return query(id * 2 + 2, tm + 1, tr, l, r);
	pii LQ = query(id * 2 + 1, tl, tm, l, tm);
	pii RQ = query(id * 2 + 2, tm + 1, tr, tm + 1, r);
	return max(LQ, RQ);
}

void init(int N, vector<int> H) {
	memset(L, -1, sizeof L);
	memset(R, -1, sizeof R);
	n = N;

	stack<int> st;
	for(int i = 1; i < N; i++) {
		while(st.size() && H[st.top()] <= H[i])
			st.pop();
		if(st.size())
			L[i] = st.top();
		else
			L[i] = -1;
		st.push(i);
	}

	stack<int> en;
	for(int i = N - 1; i >= 0; i--) {
		while(en.size() && H[en.top()] <= H[i])
			en.pop();
		if(en.size())
			R[i] = en.top();
		else
			R[i] = -1;
		en.push(i);
	}

	for(int i = 0; i < N; i++) {
		h[i] = H[i];
		if(L[i] > -1) {
			adj[i].push_back(L[i]);
			if(mn[0][H[i]] == 0)
				mn[0][H[i]] = H[L[i]];
			ono_min(mn[0][H[i]], H[L[i]]);
			ono_max(mx[0][H[i]], H[L[i]]);
			ll[0][i] = MP(H[L[i]], L[i]);
		}
		if(R[i] > -1) {
			adj[i].push_back(R[i]);
			if(mn[0][H[i]] == 0)
				mn[0][H[i]] = H[R[i]];
			ono_min(mn[0][H[i]], H[R[i]]);
			ono_max(mx[0][H[i]], H[R[i]]);
			rr[0][i] = MP(H[R[i]], R[i]);
		}
	}

	build(0, 0, n - 1);
	for(int k = 1; k < mxk; k++)
	for(int i = 1; i <= n; i++) {
		int mnj = mn[k - 1][i];
		int mxj = mx[k - 1][i];

		if(mnj) mn[k][i] = mn[k - 1][mnj];
		if(mxj) mx[k][i] = mx[k - 1][mxj];
	}

	for(int k = 1; k < mxk; k++)
	for(int i = 0; i < n; i++) {
		pii pl = ll[k - 1][i];
		pii pr = rr[k - 1][i];

		if(pl.ss) ll[k][i] = ll[k - 1][pl.ss];
		if(pr.ss) rr[k][i] = rr[k - 1][pr.ss];
	}

	// for(int i = 0; i < n; i++)
	// 	cout << R[i] << ' ';
	// cout << endl;
}

int solve(int s, int f) {
	int ans = 0;
	// cout << "solve: " << s << ' ' << f << endl;
	for(int k = mxk - 1; k >= 0; k--)
	if(mx[k][s] && mx[k][s] <= f) {
		s = mx[k][s];
		ans += (1 << k);
	}

	for(int k = mxk - 1; k >= 0; k--)
	if(mn[k][s] && mn[k][s] <= f) {
		s = mn[k][s];
		ans += (1 << k);
	}
	if(s == f) return ans;
	return INT_MAX;
}

int minimum_jumps(int A, int B, int C, int D) {
	pii bet = query(0, 0, n - 1, B + 1, C - 1);
	int bet_mx = bet.ff;
	int bet_id = bet.ss;
	// cout << endl;
	// cout << "min jump: " << A << ' ' << B << ' ' << C << ' ' << D << endl;
	// cout << "mid = " << bet_id << ' ' << bet_mx << endl;

	int l = B;
	for(int i = mxk - 1; i >= 0; i--) {
		pii p = ll[i][l];
		int hi = p.ff;
		int id = p.ss;

		if(hi == 0) continue;
		if(hi > bet_mx) continue;
		if(id < A) continue;
		l = id;
	}

	auto think = [&](int i) -> int {
		if(i == -1) return INT_MAX;
		if(i < A) return INT_MAX;

		int cur = C, cmp = max(h[i], bet_mx);
		if(cmp < h[C]) return solve(h[i], h[C]);
		for(int k = mxk - 1; k >= 0; k--) {
			pii p = rr[k][cur];
			int hi = p.ff;
			int id = p.ss;

			if(p == MP(0, 0)) continue;
			if(hi > cmp) continue;
			if(id > D) continue;
			// cout << "..." << cur << ' ' << k << endl;
			cur = id;
		}

		if(R[cur] == -1) return INT_MAX;
		if(R[cur] > D) return INT_MAX;
		if(cmp > h[R[cur]]) return INT_MAX;
		// cout << " think " << i << ' ' << R[cur] << endl;
		return solve(h[i], h[R[cur]]);
	};

	// cout << l << endl;
	int AL = think(l);
	int PL = think(L[l]);
	// cout << AL << ' ' << PL << endl;
	if(min(AL, PL) != INT_MAX) return min(AL, PL);
	return -1;
}
// 7 4 1 2 5 3 6 9 8
// 9 8 7 6 5 4 3 2 1

Compilation message (stderr)

jumps.cpp: In function 'int minimum_jumps(int, int, int, int)':
jumps.cpp:138:6: warning: unused variable 'bet_id' [-Wunused-variable]
  138 |  int bet_id = bet.ss;
      |      ^~~~~~

• Subtask 1: 4 / 4
• Subtask 2: 0 / 8
• Subtask 3: 0 / 13
• Subtask 4: 0 / 12
• Subtask 5: 23 / 23
• Subtask 6: 21 / 21
• Subtask 7: 0 / 19