Submission #603088

#	Time	Username	Problem	Language	Result	Execution time	Memory
603088		wiwiho	Shortcut (IOI16_shortcut)	C++14	0 / 100	1 ms	212 KiB

shortcut

#include "shortcut.h"

#include <bits/stdc++.h>
#include <bits/extc++.h>

#define StarBurstStream ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
#define iter(a) a.begin(), a.end()
#define riter(a) a.rbegin(), a.rend()
#define lsort(a) sort(iter(a))
#define gsort(a) sort(riter(a))
#define pb(a) push_back(a)
#define eb(a) emplace_back(a)
#define pf(a) push_front(a)
#define ef(a) emplace_front(a)
#define pob pop_back()
#define pof pop_front()
#define mp(a, b) make_pair(a, b)
#define F first
#define S second
#define mt make_tuple
#define gt(t, i) get<i>(t)
#define tomax(a, b) ((a) = max((a), (b)))
#define tomin(a, b) ((a) = min((a), (b)))
#define topos(a) ((a) = (((a) % MOD + MOD) % MOD))
#define uni(a) a.resize(unique(iter(a)) - a.begin())
#define printv(a, b) {bool pvaspace=false; \
for(auto pva : a){ \
    if(pvaspace) b << " "; pvaspace=true;\
    b << pva;\
}\
b << "\n";}

using namespace std;
using namespace __gnu_pbds;

typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;

using pii = pair<int, int>;
using pll = pair<ll, ll>;
using pdd = pair<ld, ld>;
using tiii = tuple<int, int, int>;

const ll MOD = 1000000007;
const ll MAX = 1LL << 60;

template<typename A, typename B>
ostream& operator<<(ostream& o, pair<A, B> p){
    return o << '(' << p.F << ',' << p.S << ')';
}

ll ifloor(ll a, ll b){
    if(b < 0) a *= -1, b *= -1;
    if(a < 0) return (a - b + 1) / b;
    else return a / b;
}

ll iceil(ll a, ll b){
    if(b < 0) a *= -1, b *= -1;
    if(a > 0) return (a + b - 1) / b;
    else return a / b;
}

int n;
vector<ll> p, d, s;
ll c;
vector<ll> discr;
vector<ll> tmp;
vector<ll> pos;
vector<ll> mnq, mxq;

struct event{
    ll x, y1, y2, ty;
    bool operator<(event b){
        return x < b.x;
    }
};

bool check(ll t){
    vector<event> ev;

    for(int a = n - 1; a >= 0; a--){
        ll X = t - d[a] - c;
        int id = upper_bound(iter(discr), t - d[a] + p[a]) - discr.begin();
        if(id < n){
            ll mny = -X + mxq[id];
            ll mxy = X + mnq[id];
            if(mny > mxy) return false;
            mny *= 2;
            mxy *= 2;
            ll midx = p[a] * 2;
            ll midy = (mny + mxy) / 2;
            ll r = mxy - midy;
            ll mnx = midx - r;
            ll mxx = midx + r;
            
            ll x1 = mnx - midy;
            ll x2 = mxx - midy;
            ll y1 = mnx + midy;
            ll y2 = mxx + midy;

            ev.eb(event({x1, y1, y2, 0}));
            ev.eb(event({x2 + 1, y1, y2, 1}));
        }
    }

    ll y1 = -MAX, y2 = MAX;
    ll x1 = -MAX, x2 = MAX;
    lsort(ev);
    int sz = ev.size();
    int cnt = 0;
    
    for(int i = 0; i < sz; ){
        ll x = ev[i].x;
        int tc = 0;
        bool ed = false;
        for(; i < sz && ev[i].x == x; i++){
            if(ev[i].ty == 1){
                x2 = x - 1;
                ed = true;
                break;
            }
            y1 = max(y1, ev[i].y1);
            y2 = min(y2, ev[i].y2);
            x1 = x;
            tc++;
        }
        if(y1 > y2 || ed) break;
        cnt += tc;
    }

    if(y1 > y2 || cnt != sz / 2) return false;

    for(int i = 0; i < n; i++){
        ll x = p[i] * 2;
        ll mny = max(y1 - x, x - x2);
        ll mxy = min(y2 - x, x - x1);
        auto it = lower_bound(iter(p), iceil(mny, 2));
        if(it != p.end() && *it * 2 <= mxy) return true;
    }
    return false;
}

ll find_shortcut(int _n, vector<int> len, vector<int> _d, int _c){
    n = _n;
    c = _c;
    
    p.resize(n);
    s.resize(n);
    d.resize(n);
    for(int i = 0; i < n; i++) d[i] = _d[i];
    for(int i = 0; i < n - 1; i++){
        p[i + 1] = p[i] + len[i];
    }
    for(int i = 0; i < n; i++){
        s[i] = p[i] + d[i];
    }

    discr = s;
    tmp.resize(n);
    pos.resize(n);
    mnq.resize(n);
    mxq.resize(n);
    iota(iter(tmp), 0);
    sort(iter(tmp), [&](int x, int y){ return s[x] < s[y]; });
    for(int i = 0; i < n; i++){
        pos[tmp[i]] = i;
    }
    lsort(discr);
    for(int i = n - 1; i >= 0; i--){
        mnq[i] = -d[tmp[i]] + p[tmp[i]];
        mxq[i] = d[tmp[i]] + p[tmp[i]];
        if(i < n - 1){
            mnq[i] = min(mnq[i], mnq[i + 1]);
            mxq[i] = max(mxq[i], mxq[i + 1]);
        }
    }

    ll l = 1, r = (1LL << 30) * n + 2e9 + 5;
    while(l < r){
        ll m = (l + r) / 2;
        if(check(m)) r = m;
        else l = m + 1;
    }

    return l;
}

• 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