Submission #388584

#	Time	Username	Problem	Language	Result	Execution time	Memory
388584		Keshi	Shortcut (IOI16_shortcut)	C++17	38 / 100	339 ms	210884 KiB

shortcut

//In the name of God
#include <bits/stdc++.h>
#include "shortcut.h"
using namespace std;

typedef long long ll;
typedef pair<ll, ll> pll;

const ll maxn = 2100;
const ll mod = 1e9 + 7;
const ll inf = 1e18;

#define fast_io ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#define file_io freopen("input.txt", "r+", stdin);freopen("output.txt", "w+", stdout);
#define pb push_back
#define Mp make_pair
#define F first
#define S second
#define Sz(x) ll((x).size())
#define all(x) (x).begin(), (x).end()
#define lc (id << 1)
#define rc (lc | 1)

struct node{
	ll mxr, mxl, mx;
	node(){
		mxr = mxl = mx = -inf;
	}
};

ll n, ps[maxn], d[maxn];
node seg[maxn << 2];
node dp[maxn][maxn];

node mrg(node l, node r){
	if(l.mx == -inf) return r;
	if(r.mx == -inf) return l;
	node nd;
	nd.mx = max({l.mx, r.mx, l.mxl + r.mxr});
	nd.mxl = max(l.mxl, r.mxl);
	nd.mxr = max(l.mxr, r.mxr);
	return nd;
}

void bld(ll id, ll s, ll e){
	if(e - s == 1){
		seg[id].mx = d[s];
		seg[id].mxl = d[s] - ps[s];
		seg[id].mxr = d[s] + ps[s];
		return;
	}
	ll mid = (s + e) >> 1;
	bld(lc, s, mid);
	bld(rc, mid, e);
	seg[id] = mrg(seg[lc], seg[rc]);
	return;
}
node get(ll id, ll s, ll e, ll l, ll r){
	if(r <= s || e <= l) return node();
	if(l <= s && e <= r) return seg[id];
	ll mid = (s + e) >> 1;
	return mrg(get(lc, s, mid, l, r), get(rc, mid, e, l, r));
}

void pre(){
	for(ll i = 0; i <= n; i++){
		for(ll j = i; j <= n; j++){
			dp[i][j] = get(1, 0, n, i, j);
		}
	}
}
node get(ll l, ll r){
	/*node nd;
	nd.mx = d[l];
	nd.mxl = d[l] - ps[l];
	nd.mxr = d[l] + ps[l];
	for(ll i = l + 1; i < r; i++){
		nd.mx = max(nd.mx, nd.mxl + d[i] + ps[i]);
		nd.mxl = max(nd.mxl, d[i] - ps[i]);
		nd.mxr = max(nd.mxr, d[i] + ps[i]);
	}
	return nd;*/
	//if(dp[l][r].mx != get(1, 0, n, l, r).mx) cout << "wtf " << l << " " << r << "\n";
	//cout << dp[l][r].mx << " " << get(1, 0, n, l, r).mx << "\n";
	//return get(1, 0, n, l, r);
	return dp[l][r];
}

long long find_shortcut(int N, vector<int> l, vector<int> D, int c){
	n = N;
	for(ll i = 0; i < n; i++){
		d[i] = D[i];
		ps[i + 1] = ps[i] + l[i];
	}
	bld(1, 0, n);
	pre();
	ll ans = get(0, n).mx;
	for(ll i = 0; i < n; i++){
		for(ll j = i + 1; j < n; j++){
			ll C = ps[j] - ps[i] + c;
			ll x = get(0, i + 1).mxl + get(j, n).mxr - max(0ll, (ps[j] - ps[i]) - c);
//			cout << "! " << x << "\n";
			x = max(x, get(0, i + 1).mx);
//			cout << "! " << x << "\n";
			x = max(x, get(j, n).mx);
//			cout << "! " << x << "\n";
//			cout << "^ " << C << "\n";
			ll ptr = i;
			ll mx1 = min((ll)c, C - c) + d[j], mx2 = min((ll)c, C - c) + d[j];
			for(ll k = i; k < j; k++){
				mx1 = max(mx1, d[k] + min(ps[k] - ps[i], C + ps[i] - ps[k]));
//				cout << "! " << min(ps[k] - ps[i], C + ps[i] - ps[k]) << " " <<min(ps[j] - ps[k], C + ps[k] - ps[j]) << "\n";
				mx2 = max(mx2, d[k] + min(ps[j] - ps[k], C + ps[k] - ps[j]));
				while(ptr <= j && ps[ptr] - ps[k] < C + ps[k] - ps[ptr]) ptr++;
//				cout << "# " << k << " " << ptr << "\n";
				x = max(x, d[k] - ps[k] + get(k + 1, ptr).mxr);
//			cout << "! " << x << "\n";
				x = max(x, C + d[k] + ps[k] + get(ptr, j + 1).mxl);
//			cout << "! " << x << "\n";
			}
			x = max(x, mx2 + get(j + 1, n).mxr - ps[j]);
//			cout << "! " << x << "\n";
//			cout << mx1 << " " << get(0, i).mxl + ps[i] << "\n";
			x = max(x, mx1 + get(0, i).mxl + ps[i]);
//			cout << "! " << x << "\n";
//			if(x == 100) cout << "$ " << i << " " << j << "\n";
			ans = min(ans, x);
		}
	}
	return ans;
}

/*int main(){
    fast_io;



    return 0;
}*/

• Subtask 1: 9 / 9
• Subtask 2: 14 / 14
• Subtask 3: 8 / 8
• Subtask 4: 7 / 7
• Subtask 5: 0 / 33
• Subtask 6: 0 / 22
• Subtask 7: 0 / 4
• Subtask 8: 0 / 3