Submission #570660

#	Time	Username	Problem	Language	Result	Execution time	Memory
570660		balbit	IOI Fever (JOI21_fever)	C++14	57 / 100	1213 ms	38432 KiB

fever

#include <bits/stdc++.h>
#define int ll
using namespace std;
#define ll long long
#define y1 zck_is_king
#define pii pair<ll, ll>
#define ull unsigned ll
#define f first
#define s second
#define ALL(x) x.begin(),x.end()
#define SZ(x) (int)x.size()
#define SQ(x) (x)*(x)
#define MN(a,b) a = min(a,(__typeof__(a))(b))
#define MX(a,b) a = max(a,(__typeof__(a))(b))
#define pb push_back
#define REP(i,n) for (int i = 0; i<n; ++i)
#define RREP(i,n) for (int i = n-1; i>=0; --i)
#define REP1(i,n) for (int i = 1; i<=n; ++i)
#define SORT_UNIQUE(c) (sort(c.begin(),c.end()), c.resize(distance(c.begin(),unique(c.begin(),c.end()))))
#ifdef BALBIT
#define IOS()
#define bug(...) fprintf(stderr,"#%d (%s) = ",__LINE__,#__VA_ARGS__),_do(__VA_ARGS__);
template<typename T> void _do(T &&x){cerr<<x<<endl;}
template<typename T, typename ...S> void _do(T &&x, S &&...y){cerr<<x<<", ";_do(y...);}
#else
#define IOS() ios_base::sync_with_stdio(0);cin.tie(0);
#define endl '\n'
#define bug(...)
#endif

const int iinf = 1e9+10;
const ll inf = 0x3f3f3f3f3f3f3f3f;
const ll mod = 1e9+7 ;


void GG(){cout<<"0\n"; exit(0);}

ll mpow(ll a, ll n, ll mo = mod){ // a^n % mod
    ll re=1;
    while (n>0){
        if (n&1) re = re*a %mo;
        a = a*a %mo;
        n>>=1;
    }
    return re;
}

ll inv (ll b, ll mo = mod){
    if (b==1) return b;
    return (mo-mo/b) * inv(mo%b,mo) % mo;
}

const int maxn = 1e5+5;

int n;
struct pt{
    int x,y;
    void in(){
        cin>>x>>y;
        x*=2; y*=2;
    }
    int dist(pt &o) {
        return abs(o.x-x) + abs(o.y-y);
    }
    pt operator - (pt &o) {
        return {x - o.x, y - o.y};
    }
};

pt P[maxn];
ll dst[maxn];
int dir[maxn];
bool done[maxn];

pii D4[4] = {{1,0}, {0,1}, {-1,0}, {0,-1}};
pii Dia4[4] = {{1,1},{-1,1},{-1,-1},{1,-1}};

inline int diagof(pii & p) {
    return find(Dia4, Dia4+4, p) - Dia4;
}

inline int F4(int x) {
    return x<0?x+4:(x>=4?x-4:x);
}

inline pt unrot(pt p, int d) {
    if (d == 0) return p;
    if (d == 1) return {p.y, -p.x};
    if (d == 2) return {-p.x, -p.y};
    if (d == 3) return {-p.y, p.x};
}

map<int, set<pair<int, int> > > MP[4][2];
//map<int, set<pair<int, int> > > DONE[4][2];
ll closest[maxn][2];

int run(int idir){
    bug(idir);
    dir[0] = idir;
    memset(done, 0, sizeof done);
    REP(i,4) REP(j,2) {
        MP[i][j].clear();
//        DONE[i][j].clear();
    }
    REP1(i,n-1) {
        int x = P[i].x, y = P[i].y;
        if (x == y || x == -y) {
            assert(x && y);
            pii tmp = {x/abs(x), y/abs(x)};
            int at = diagof(tmp);
            if (at == idir) {
                dir[i] = F4(idir-1);
            }else if (at == F4(idir-1)) {
                dir[i] = F4(idir+1);
            }else{
                dir[i] = idir;
            }
        }else{
            dir[i] = (y<x?vector<int>{1,2}:vector<int>{0,3})[y>-x];
        }
        bug(i, dir[i]);

    }

    REP(i,n) {
        // build the maps
        {
            int nd = F4(dir[i] + 1);
            pt at = unrot(P[i], nd);
            MP[nd][0][at.x - at.y].insert({at.x, i});
        }
        {
            int nd = F4(dir[i] - 1);
            pt at = unrot(P[i], nd);
            MP[nd][1][at.x + at.y].insert({at.x, i});
        }
    }

    priority_queue<pii, vector<pii>, greater<pii> > pq;
    pq.push({0,0});

    memset(dst, 0x3f, sizeof dst);
    memset(closest, 0x3f, sizeof closest);
    dst[0] = 0;

    auto UPD = [&](int u, int d, bool branch) {
        MN(closest[u][branch], d);
        if (dst[u] > d) {
            dst[u] = d;
            pq.push({dst[u], u});
        }
    };

    while (!pq.empty())  {
        int v = pq.top().s; ll w = pq.top().f; pq.pop();
        if (done[v] || dst[v] != w) continue;
        done[v] = 1;

        int dr = dir[v];
        pt R = unrot(P[v], dr);

        auto gt0 = MP[dr][0][R.x-R.y].lower_bound({R.x + w,-1});
        if (gt0 != MP[dr][0][R.x-R.y].end()) {
            UPD(gt0->s, gt0->f - R.x, 1);
        }

        auto gt1 = MP[dr][1][R.x+R.y].lower_bound({R.x + w,-1});
        if (gt1 != MP[dr][1][R.x+R.y].end()) {
            UPD(gt1->s, gt1->f - R.x, 0);
        }

        {
            int nd = F4(dir[v] + 1);
            pt at = unrot(P[v], nd);
            auto clo1 = MP[nd][0][at.x - at.y].lower_bound({at.x+1, -1});
            // from my perspective, it is the 1-branch
            if (clo1 != MP[nd][0][at.x - at.y].end()) {
                UPD(clo1->s, closest[v][1] + (clo1->f) - at.x, 1);
            }

            MP[nd][0][at.x - at.y].erase({at.x, v});
        }
        {
            int nd = F4(dir[v] - 1);
            pt at = unrot(P[v], nd);
            auto clo0 = MP[nd][1][at.x + at.y].lower_bound({at.x+1, -1});
            // from my perspective, it is the 0-branch
            if (clo0 != MP[nd][1][at.x + at.y].end()) {
                UPD(clo0->s, closest[v][0] + (clo0->f) - at.x, 0);
            }

            MP[nd][1][at.x + at.y].erase({at.x, v});
        }


    }
    int re = 0;
    REP(i,n) {
        if (dst[i] != inf) {
            bug(i, dst[i]);
            ++re;
        }
    }
    return re;
}

signed main(){
    IOS();
    cin>>n;

    REP(i,n) {
        P[i].in();
        if (i) {
            P[i].x -= P[0].x; P[i].y -= P[0].y;
        }
    }
    P[0] = {0,0};
    int re = 0;
    REP(idir, 4) {
        MX(re, run(idir));
    }
    cout<<re<<endl;
}

Compilation message (stderr)

fever.cpp: In function 'pt unrot(pt, long long int)':
fever.cpp:91:1: warning: control reaches end of non-void function [-Wreturn-type]
   91 | }
      | ^

• Subtask 1: 5 / 5
• Subtask 2: 8 / 8
• Subtask 3: 6 / 6
• Subtask 4: 6 / 6
• Subtask 5: 0 / 12
• Subtask 6: 32 / 32
• Subtask 7: 0 / 31