Submission #1042746

#	Time	Username	Problem	Language	Result	Execution time	Memory
1042746		Zicrus	Shortcut (IOI16_shortcut)	C++17	0 / 100	0 ms	348 KiB

shortcut

#include <bits/stdc++.h>
#include "shortcut.h"
using namespace std;

typedef long long ll;

ll find_shortcut(int n, vector<int> l, vector<int> s, int c) {
    vector<ll> dist(n);
    vector<pair<ll, ll>> preMax(n), postMax(n);
    preMax[0] = {s[0], 0};
    for (int i = 1; i < n; i++) {
        dist[i] = dist[i-1] + l[i-1];
        preMax[i] = {dist[i] + s[i], i};
        if (preMax[i-1].first > preMax[i].first) preMax[i] = preMax[i-1];
    }
    postMax[n-1] = {dist[n-1] + s[n-1], n-1};
    for (int i = n-2; i >= 0; i--) {
        postMax[i] = {dist[i] + s[i], i};
        if (postMax[i+1].first > postMax[i].first) postMax[i] = postMax[i+1];
    }

    ll res = 1ll << 62ll;
    for (int low = 0; low < n-1; low++) {
        for (int high = low+1; high < n; high++) {
            // First search
            ll mx = preMax[low].first, mxId = preMax[low].second;
            ll mxFromHigh = postMax[high].first - (dist[high] - dist[low]) + min(dist[high] - dist[low], (ll)c);
            if (mxFromHigh > mx) {
                mx = mxFromHigh;
                mxId = postMax[high].second;
            }
            for (int i = low+1; i < high; i++) {
                ll val = min(dist[i], dist[low] + c + (dist[high] - dist[i])) + s[i];
                if (val > mx) {
                    mx = val;
                    mxId = i;
                }
            }

            // Second search
            ll diaRes = 0;
            ll dst = 0;
            ll dia = 0;
            for (int i = mxId-1; i >= 0; i--) {
                dst += l[i];
                ll ths = min(dst, abs(dist[mxId] - dist[high]) + c + abs(dist[low] - dist[i])) + s[i];
                dia = max(dia, ths);
            }
            dst = 0;
            for (int i = mxId+1; i < n; i++) {
                dst += l[i-1];
                ll ths = min(dst, abs(dist[mxId] - dist[low]) + c + abs(dist[high] - dist[i])) + s[i];
                dia = max(dia, ths);
            }
            dia += s[mxId];
            diaRes = dia;

            mxId = postMax[0].second;
            dst = 0;
            dia = 0;
            for (int i = mxId-1; i >= 0; i--) {
                dst += l[i];
                ll ths = min(dst, abs(dist[mxId] - dist[high]) + c + abs(dist[low] - dist[i])) + s[i];
                dia = max(dia, ths);
            }
            dst = 0;
            for (int i = mxId+1; i < n; i++) {
                dst += l[i-1];
                ll ths = min(dst, abs(dist[mxId] - dist[low]) + c + abs(dist[high] - dist[i])) + s[i];
                dia = max(dia, ths);
            }
            dia += s[mxId];
            diaRes = max(diaRes, dia);

            res = min(res, dia);
        }
    }

    return res;
}

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