Submission #515192

#	Time	Username	Problem	Language	Result	Execution time	Memory
515192		minhcool	Rainforest Jumps (APIO21_jumps)	C++17	100 / 100	1430 ms	68508 KiB

jumps

#include<bits/stdc++.h>
using namespace std;
 
//#define int long long
#define fi first
#define se second
#define pb push_back
#define mp make_pair
#define foru(i, l, r) for(int i = l; i <= r; i++)
#define ford(i, r, l) for(int i = r; i >= l; i--)
 
typedef pair<int, int> ii;
typedef pair<ii, int> iii;
typedef pair<ii, ii> iiii;
 
const int N = 3e5 + 5;
 
const int oo = 1e9 + 7, mod = 1e9 + 7;
 
int n, h[N], lg2[N];
 
int nxtl[N], nxtr[N];
 
int small_jump[N][20], large_jump[N][20];
 
ii mx[N][20];
 
void init(int _n, vector<int> _H){
	n = _n;
	for(int i = 1; i <= n; i++) h[i] = _H[i - 1];
	h[0] = h[n + 1] = oo;
	stack<int> stk;
	stk.push(0);
	for(int i = 1; i <= n; i++) lg2[i] = log2(i);
	for(int i = 1; i <= n; i++){
		while(h[stk.top()] < h[i]) stk.pop();
		nxtl[i] = stk.top();
		stk.push(i);
	}
    //return;
	while(!stk.empty()) stk.pop();
	stk.push(n + 1);
	for(int i = n; i >= 1; i--){
		while(h[stk.top()] < h[i]) stk.pop();
		nxtr[i] = stk.top();
		stk.push(i);
	}
    //return;
	for(int i = 1; i <= n; i++){
		small_jump[i][0] = (h[nxtl[i]] < h[nxtr[i]] ? nxtl[i] : nxtr[i]);
		large_jump[i][0] = (h[nxtl[i]] > h[nxtr[i]] ? nxtl[i] : nxtr[i]);
	}
	for(int i = 1; i <= n; i++) mx[i][0] = {h[i], i};
//	cout << "OKAY\n";
	for(int i = 1; i <= 19; i++){
		for(int j = 1; (j + (1LL << i) - 1) <= n; j++){
			mx[j][i] = max(mx[j][i - 1], mx[j + (1LL << (i - 1))][i - 1]);
			//cout << i << " " << j << " " << mx[j][i].fi << "\n";
		}
	}
	for(int i = 1; i <= 19; i++){
		for(int j = 1; j <= n; j++){
			small_jump[j][i] = small_jump[small_jump[j][i - 1]][i - 1];
			large_jump[j][i] = large_jump[large_jump[j][i - 1]][i - 1];
		}
	}
}
 
ii maxi(int l, int r){
	if(l > r) return {-oo, -oo};
	//cout << r - l + 1 << " " << lg2[r - l + 1] << "\n";
	int k = lg2[r - l + 1];
	//cout << mx[l][k].fi << " " << mx[r - (1LL << k) + 1][k].fi << "\n";
	return max(mx[l][k], mx[r - (1LL << k) + 1][k]);
}
 
int cal(int a, int c){
	int answer = 0;
	for(int i = 19; i >= 0; i--){
		if(h[large_jump[a][i]] <= h[c]){
			answer += (1LL << i);
			a = large_jump[a][i];
		}
	}
	for(int i = 19; i >= 0; i--){
		if(h[small_jump[a][i]] <= h[c]){
			answer += (1LL << i);
			a = small_jump[a][i];
		}
	}
	if(a != c) return oo;
	else return answer;
}
 
int cal2(int a, int b, int c){
	//assert(c == d);
	if(h[b] > h[c]){
		return oo;
	}
	int l = a, r = b;
	while(l < r){
		int mid = (l + r) >> 1;
		if(maxi(mid, b).fi > h[c]) l = mid + 1;
		else r = mid;
	}
	//cout << l << " " << b << " " << c << "\n";
	int pos = maxi(l, b).se;
	return cal(pos, c);
}
 
int minimum_jumps(int a, int b, int c, int d){
    //return -1;
	a++, b++, c++, d++;
	//cout << "OK " << a << " " << b << " " << c << " "<< d << "\n";
	if(b == (c - 1)){
		if(h[b] > maxi(c, d).fi) return -1;
		else return 1;
	}
	ii temp1 = maxi(a, b), temp2 = maxi(b + 1, c - 1), temp3 = maxi(c, d);
	//cout << temp1.fi << " " << temp2.fi << " " << temp3.fi << "\n";
	//cout << b + 1 << " " << c - 1 << " " << temp2.fi << " " << temp2.se << "\n";
	if(min(temp1.fi, temp3.fi) > temp2.fi){
        //assert(0);
		int l = a, r = b;
		while(l < r){
			int mid = (l + r + 1) >> 1;
			if(maxi(mid, b).fi < temp2.fi) r = mid - 1;
			else l = mid;
		}
		//cout << l << "\n";
		if(temp3.fi > h[l]) return 1;
		else a = l + 1;
	}
	if(temp3.fi < temp2.fi || a > b) return -1;
	int answer = oo;
	answer = min(answer, cal2(a, b, temp2.se) + 1);
	//cout << answer << "\n";
    if(c == d){
        //assert(answer >= cal2(a, b, c));
    }
	if(a && maxi(1, a - 1).fi > temp2.fi){
		int l = 1, r = a - 1;
		while(l < r){
			int mid = (l + r + 1) >> 1;
			if(maxi(mid, a - 1).fi < temp2.fi) r = mid - 1;
			else l = mid;
		}
		if(h[l] < temp3.fi) answer = min(answer, cal2(a, b, l) + 1);
	}
    if(c == d){
    	//cout << answer << " " << cal2(a, b, c) << "\n";
		assert(answer >= cal2(a, b, c));
    }
	return (answer == oo ? -1 : answer);
}

/*
 
int _n;
vector<int> _h;

void process(){
	cin >> _n;
	for(int i = 1; i <= _n; i++){
		int x;
		cin >> x;
		_h.pb(x);
	}
	init(_n, _h);
	int q;
	cin >> q;
	while(q--){
		int a, b, c, d;
		cin >> a >> b >> c >> d;
		cout << minimum_jumps(a, b, c, d) << "\n";
	}
}
 
signed main(){
	ios_base::sync_with_stdio(0);
	//freopen("jumps.inp", "r", stdin);
	//freopen("jumps.out", "w", stdout);
	process();
}
*/
/*
7
3 2 1 6 4 5 7
1
4 4 6 6
*/

• 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