Submission #74247

#	Time	Username	Problem	Language	Result	Execution time	Memory
74247		imeimi2000	Shortcut (IOI16_shortcut)	C++14	97 / 100	2017 ms	270496 KiB

shortcut

#include "shortcut.h"
#include <algorithm>
#include <functional>

using namespace std;
typedef long long llong;
typedef pair<llong, llong> pll;

int n, c;
vector<llong> S;
vector<int> D;
    
vector<pll> Mord;
vector<pll> Pord;
vector<pll> Pmn1;
vector<llong> Pmn2;

const llong inf = 1e18;
int check(llong X) {
    llong mxP = -inf, mxM = -inf;
    llong mnP = inf, mnM = inf;
    for (int i = 0, j = 0; i < n; ++i) {
        llong it, v;
        tie(v, it) = Mord[i];
        while (j < n && Pord[j].first <= X + v) ++j;
        llong mP = -inf;
        for (int k = n - 1; j <= k; --k) if (Pord[k].second != it) {
            mP = Pord[k].first;
            break;
        }
        llong mM = (j < n ?
                (Pmn1[j].second != it ? Pmn1[j].first : Pmn2[j]) : inf);
        mxP = max(mxP, S[it] + D[it] + mP - (X - c));
        mxM = max(mxM, S[it] + D[it] - mM - (X - c));
        mnP = min(mnP, v + mM + (X - c));
        mnM = min(mnM, v - mP + (X - c));
        
        if (mnP < mxP) return 0;
        if (mnM < mxM) return 0;
    }
    
    for (int i = 0, mn = 0, mx = 0; i < n; ++i) {
        llong LB = max(mxP - S[i], S[i] - mnM);
        llong UB = min(mnP - S[i], S[i] - mxM);
        while (mn < n && S[mn] < LB) ++mn;
        while (0 < mn && LB <= S[mn - 1]) --mn;
        
        while (mx < n && S[mx] <= UB) ++mx;
        while (0 < mx && UB < S[mx - 1]) --mx;
        
        if (mn < mx) return 1;
    }
    return 0;
}

llong find_shortcut(int N, vector<int> L, vector<int> E, int C) {
    n = N; c = C;
    S.push_back(0);
    for (int i : L) S.push_back(S.back() + i);
    D = E;
    
    for (int i = 0; i < n; ++i) {
        Mord.emplace_back(S[i] - D[i], i);
        Pord.emplace_back(S[i] + D[i], i);
    }
    sort(Mord.begin(), Mord.end());
    sort(Pord.begin(), Pord.end());
    Pmn1.resize(n, pll(inf, -1)); Pmn2.resize(n, inf);
    for (int i = n; i--; ) {
        int it = Pord[i].second;
        llong v = S[it] - D[it];
        if (v < Pmn1[i].first) Pmn2[i] = Pmn1[i].first, Pmn1[i] = pll(v, it);
        else if (v < Pmn2[i]) Pmn2[i] = v;
        if (i) Pmn1[i - 1] = Pmn1[i], Pmn2[i - 1] = Pmn2[i];
    }
    
    sort(E.begin(), E.end());
    llong s = E[n - 2] + E[n - 1], e = inf;
    while (s < e) {
        llong m = (s + e) / 2;
        if (check(m)) e = m;
        else s = m + 1;
    }
    return s;
}

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