Submission #1077026

#	Time	Username	Problem	Language	Result	Execution time	Memory
1077026		Trent	Overtaking (IOI23_overtaking)	C++17	39 / 100	3539 ms	35104 KiB

overtaking

#include "overtaking.h"
#include "bits/stdc++.h"
using namespace std;
#define forR(i, x) for(int i = 0; i < (x); ++i)
#define REP(i, a, b) for(int i = (a); i < (b); ++i)
#define all(x) x.begin(), x.end()
#define asst(x) if(!(x)) exit(2)
typedef long long ll;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<vi> vvi;
typedef vector<vll> vvll;
struct bus {
    ll t; int w;
};
struct ivl {
    ll l, r, ans;
};
vvll t, e, me;
vi pos;
int X;
vector<vector<ivl>> stored;

struct segTree {
    struct node {
        ll val;
        bool lz;
    };
    vector<node> seg;
    vi& vls;
    int cl, cr;
    segTree(vi& vals) : vls(vals), cl(0), cr((int) vals.size() - 1) {
        seg.resize(4 * vals.size(), {-1, false});
    }
    void push(int v, int l, int r) {
        if(l < r) {
            if(seg[v].lz) {
                seg[2*v].val = seg[v].val, seg[2*v+1].val = seg[v].val;
                seg[2*v].lz = seg[2*v+1].lz = true;
                seg[v].lz = false;
                seg[v].val = -1;
            }
        }
    }
    void upd(int v, int nl, int nr, int l, int r, ll to) {
        push(v, nl, nr);
        if(l > r) return;
        if(nl == l && nr == r) {
            seg[v].val = to;
            seg[v].lz = true;
        } else {
            int mid = (nl+nr)/2;
            upd(2*v, nl, mid, l, min(r, mid), to);
            upd(2*v+1, mid+1, nr, max(mid+1, l), r, to);
        }
    }
    ll qu(int v, int nl, int nr, int i) {
        if(nl == i && nr == i) return seg[v].val;
        int mid = (nl+nr)/2;
        if(i <= mid) return qu(2*v, nl, mid, i);
        else return qu(2*v+1, mid+1, nr, i);
    }
    int binSearch(ll val) {
        auto nex = lower_bound(all(this->vls), val);
        asst(nex != this->vls.end() && *nex == val);
        return nex - vls.begin();
    }
    void upd(ll l, ll r, ll to) {
        upd(1, cl, cr, binSearch(l), binSearch(r), to);
    }
    ll qu(ll i) {
        return qu(1, cl, cr, binSearch(i));
    }
};
segTree* seg = nullptr;

void sortByTime(vector<bus>& bs) {
    sort(all(bs), [](bus a, bus b){return a.t < b.t;});
}
void init(int L, int N, std::vector<long long> T, std::vector<int> W, int X, int M, std::vector<int> S)
{
    vll nt; vi nw;
    set<int> rem;
    forR(i, N) if(W[i] <= X) rem.insert(i);
    forR(i, N) if(!rem.count(i)) {
        nt.push_back(T[i]);
        nw.push_back(W[i]);
    }
    N -= rem.size();
    T = nt, W = nw;

    t = vvll(M, vll(N)), e = vvll(M-1, vll(N)), me = vvll(M-1, vll(N));
    pos = S;
    vector<bus> bs;
    forR(i, N) {
        bs.push_back({T[i], W[i]});
    }
    forR(i, M-1) {
        sortByTime(bs);
        forR(j, N) t[i][j] = bs[j].t;
        forR(j, N) e[i][j] = bs[j].t + (ll) bs[j].w * (S[i+1] - S[i]);
        ll cm = 0;
        for(int j = 0; j < N; ){
            ll cur = bs[j].t;
            int k=j;
            for(; k < N && bs[k].t == cur; ++k) {}
            REP(l, j, k) bs[l].t = max(e[i][l], cm);
            REP(l, j, k) cm = max(cm, e[i][l]);
            j = k;
        }
    }
    forR(j, N) t[M-1][j] = bs[j].t;
    ::X = X;
    forR(i, M-1) {
        if(N > 0) me[i][0] = e[i][0];
        REP(j, 1, N) me[i][j] = max(e[i][j], me[i][j-1]);
    }

    stored = vector<vector<ivl>>(M-1);
    for(int i = M-2; i >= 0; --i) {
        ll toNex = (ll) X * (S[i+1]-S[i]), toHere = (ll) X * (S[i] - S[0]);
        forR(j, N) {
            ll lo = t[i][j]+1;
            ll hi = j == N-1 ? me[i][j] - toNex : min(me[i][j] - toNex, t[i][j+1]);

            ll nlo = lo - toHere, nhi = hi - toHere;
            ll find = me[i][j] - toNex - toHere;
            bool found = false;
            for(int k = i+1; !found && k < M-1; ++k) {
                for(auto [l, r, cAns] : stored[k]) {
                    if(l <= find && r >= find) {
                        asst(!found);
                        found = true;
                        stored[i].push_back({nlo, nhi, cAns});
                    }
                }
            }
            if(!found) stored[i].push_back({nlo, nhi, me[i][j] + (ll) X * (S[M-1] - S[i+1])});
        }
    }
}

long long arrival_time(long long Y)
{
    int M = (int) pos.size(), N = t[0].size();
    forR(i, M-1) {
        for(auto [l, r, ans] : stored[i]) {
            if(l <= Y && r >= Y) return ans;
        }
    }
    return Y + (ll) X * (pos[M-1] - pos[0]);
}

Compilation message (stderr)

overtaking.cpp: In function 'long long int arrival_time(long long int)':
overtaking.cpp:145:31: warning: unused variable 'N' [-Wunused-variable]
  145 |     int M = (int) pos.size(), N = t[0].size();
      |                               ^

• Subtask 0: 0 / 0
• Subtask 1: 9 / 9
• Subtask 2: 10 / 10
• Subtask 3: 20 / 20
• Subtask 4: 0 / 26
• Subtask 5: 0 / 35