Submission #973742

#	Time	Username	Problem	Language	Result	Execution time	Memory
973742		dubabuba	Rainforest Jumps (APIO21_jumps)	C++14	27 / 100	1423 ms	172816 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;
const int inf = 1e9 + 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(inf, -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;

	for(int i = 0; i <= N; i++)
	for(int k = 0; k < mxk; k++) {
		mn[k][i] = mx[k][i] = 0;
		ll[k][i] = rr[k][i] = MP(0, 0);
	}

	stack<int> st;
	for(int i = 0; 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];
	}
}

int solve(int s, int f) {
	if(s == f) return 0;
	int ans = 0;
	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 inf;
}

int go_L(int i) { if(i < 0) return -1; return L[i]; }
int go_R(int i) { if(i < 0) return -1; return R[i]; }
int GIS(int l, int r, int upper, bool rev) {
	// if(rev)
	// 	cout << "find " << l << ' ' << r << ": " << upper << endl;
	if(r < l) return -1;
	int cur = (rev) ? r : l;

	for(int k = mxk - 1; k >= 0; k--) {
		pii p = (rev) ? ll[k][cur] : rr[k][cur];
		int hi = p.ff;
		int id = p.ss;

		if(hi == 0) continue;
		if(hi > upper) continue;
		if(id < l || r < id) continue;
		// if(rev) cout << cur << ' ';
		cur = id;
	}
	// if(rev)
	// 	cout << cur << endl;
	if(h[cur] > upper) return cur;
	return (rev) ? cur : go_R(cur);
}


int minimum_jumps(int A, int B, int C, int D) {
	pii PM = query(0, 0, n - 1, B + 1, C - 1);
	pii PL = query(0, 0, n - 1, A, B);
	pii PR = query(0, 0, n - 1, C, D);
	if(PM.ss >= 0 && PM.ff > PR.ff) return -1;

	auto think = [&](int st, int en, bool ML, bool MR) -> int {
		if(st == -1 || en == -1) return inf;
		if(ML) if(st < A || B < st) return inf;
		if(MR) if(en < C || D < en) return inf;
		if(st == en) return 0;
		return solve(h[st], h[en]);
	};

	// cout << endl;
	// cout << A << ' ' << B << " -> " << C << ' ' << D << endl;
	int gay = (PM.ff == inf) ? 0 : PM.ff;

	auto find_en = [&](int st) -> int {
		if(st == -1) return -1;
		int en = GIS(C, D, max(gay, h[st]), 0);
		return en;
	};

	int st1 = GIS(A, B, PM.ff, 1);
	int st2 = go_R(st1);
	int st3 = B;
	int st4 = PL.ss;

	int en1 = find_en(st1);
	int en2 = find_en(st2);
	int en3 = find_en(st3);
	int en4 = find_en(st4);

	int ans1 = think(st1, en1, 1, 1);
	int ans2 = think(st2, en2, 1, 1);
	int ans3 = think(st3, en3, 1, 1);
	int ans4 = think(st4, en4, 1, 1);

	// cout << st1 << ' ' << en1 << " = " << ans1 << endl;
	// cout << st2 << ' ' << en2 << " = " << ans2 << endl;
	// cout << st3 << ' ' << en3 << " = " << ans3 << endl;
	// cout << st4 << ' ' << en4 << " = " << ans4 << endl;

	int sda = inf;
	if(PM.ff > PL.ff) {
		int st = PL.ss;
		int mid = GIS(0, A - 1, PM.ff, 1);
		int en = (mid > -1) ? GIS(C, D, h[mid], 0) : -1;

		sda = think(st, mid, 1, 0) + think(mid, en, 0, 1);
		// cout << st << ' ' << mid << ' ' << en << " = " << sda << endl;
	}

	int ans = inf;
	ono_min(ans, ans1);
	ono_min(ans, ans2);
	ono_min(ans, ans3);
	ono_min(ans, ans4);
	ono_min(ans, sda);

	return (ans < inf) ? ans : -1;	
}
// 7 4 1 2 5 3 6 9 8
// 9 8 7 6 5 4 3 2 1

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