Submission #337020

#	Time	Username	Problem	Language	Result	Execution time	Memory
337020		rqi	Bulldozer (JOI17_bulldozer)	C++14	80 / 100	2090 ms	83000 KiB

bulldozer

#include <bits/stdc++.h>
using namespace std;
 
typedef long long ll;
typedef long double ld;
typedef double db; 
typedef string str; 

typedef pair<int,int> pi;
typedef pair<ll,ll> pl; 
typedef pair<db,db> pd; 

typedef vector<int> vi; 
typedef vector<bool> vb; 
typedef vector<ll> vl; 
typedef vector<db> vd; 
typedef vector<str> vs; 
typedef vector<pi> vpi;
typedef vector<pl> vpl; 
typedef vector<pd> vpd; 

#define mp make_pair
#define f first
#define s second
#define sz(x) (int)(x).size()
#define all(x) begin(x), end(x)
#define rall(x) (x).rbegin(), (x).rend() 
#define sor(x) sort(all(x)) 
#define rsz resize
#define ins insert 
#define ft front() 
#define bk back()
#define pf push_front 
#define pb push_back
#define eb emplace_back 
#define lb lower_bound 
#define ub upper_bound 

#define FOR(i,a,b) for (int i = (a); i < (b); ++i)
#define F0R(i,a) FOR(i,0,a)
#define ROF(i,a,b) for (int i = (b)-1; i >= (a); --i)
#define R0F(i,a) ROF(i,0,a)
#define trav(a,x) for (auto& a: x)

const int MOD = 1e9+7; // 998244353;
const int MX = 2e5+5; 
const ll INF = 1e18; 
const ld PI = acos((ld)-1);
const int xd[4] = {1,0,-1,0}, yd[4] = {0,1,0,-1}; 
mt19937 rng((uint32_t)chrono::steady_clock::now().time_since_epoch().count()); 

template<class T> bool ckmin(T& a, const T& b) { 
    return b < a ? a = b, 1 : 0; }
template<class T> bool ckmax(T& a, const T& b) { 
    return a < b ? a = b, 1 : 0; } 
constexpr int pct(int x) { return __builtin_popcount(x); } 
constexpr int bits(int x) { return 31-__builtin_clz(x); } // floor(log2(x)) 
ll cdiv(ll a, ll b) { return a/b+((a^b)>0&&a%b); } // divide a by b rounded up
ll fdiv(ll a, ll b) { return a/b-((a^b)<0&&a%b); } // divide a by b rounded down
ll half(ll x) { return fdiv(x,2); }

template<class T, class U> T fstTrue(T lo, T hi, U f) { 
    // note: if (lo+hi)/2 is used instead of half(lo+hi) then this will loop infinitely when lo=hi
    hi ++; assert(lo <= hi); // assuming f is increasing
    while (lo < hi) { // find first index such that f is true 
        T mid = half(lo+hi);
        f(mid) ? hi = mid : lo = mid+1; 
    } 
    return lo;
}
template<class T, class U> T lstTrue(T lo, T hi, U f) {
    lo --; assert(lo <= hi); // assuming f is decreasing
    while (lo < hi) { // find first index such that f is true 
        T mid = half(lo+hi+1);
        f(mid) ? lo = mid : hi = mid-1;
    } 
    return lo;
}
template<class T> void remDup(vector<T>& v) { 
    sort(all(v)); v.erase(unique(all(v)),end(v)); }

// INPUT
template<class A> void re(complex<A>& c);
template<class A, class B> void re(pair<A,B>& p);
template<class A> void re(vector<A>& v);
template<class A, size_t SZ> void re(array<A,SZ>& a);

template<class T> void re(T& x) { cin >> x; }
void re(db& d) { str t; re(t); d = stod(t); }
void re(ld& d) { str t; re(t); d = stold(t); }
template<class H, class... T> void re(H& h, T&... t) { re(h); re(t...); }

template<class A> void re(complex<A>& c) { A a,b; re(a,b); c = {a,b}; }
template<class A, class B> void re(pair<A,B>& p) { re(p.f,p.s); }
template<class A> void re(vector<A>& x) { trav(a,x) re(a); }
template<class A, size_t SZ> void re(array<A,SZ>& x) { trav(a,x) re(a); }

// TO_STRING
#define ts to_string
str ts(char c) { return str(1,c); }
str ts(const char* s) { return (str)s; }
str ts(str s) { return s; }
str ts(bool b) { 
    #ifdef LOCAL
        return b ? "true" : "false"; 
    #else 
        return ts((int)b);
    #endif
}
template<class A> str ts(complex<A> c) { 
    stringstream ss; ss << c; return ss.str(); }
str ts(vector<bool> v) {
    str res = "{"; F0R(i,sz(v)) res += char('0'+v[i]);
    res += "}"; return res; }
template<size_t SZ> str ts(bitset<SZ> b) {
    str res = ""; F0R(i,SZ) res += char('0'+b[i]);
    return res; }
template<class A, class B> str ts(pair<A,B> p);
template<class T> str ts(T v) { // containers with begin(), end()
    #ifdef LOCAL
        bool fst = 1; str res = "{";
        for (const auto& x: v) {
            if (!fst) res += ", ";
            fst = 0; res += ts(x);
        }
        res += "}"; return res;
    #else
        bool fst = 1; str res = "";
        for (const auto& x: v) {
            if (!fst) res += " ";
            fst = 0; res += ts(x);
        }
        return res;

    #endif
}
template<class A, class B> str ts(pair<A,B> p) {
    #ifdef LOCAL
        return "("+ts(p.f)+", "+ts(p.s)+")"; 
    #else
        return ts(p.f)+" "+ts(p.s);
    #endif
}

// OUTPUT
template<class A> void pr(A x) { cout << ts(x); }
template<class H, class... T> void pr(const H& h, const T&... t) { 
    pr(h); pr(t...); }
void ps() { pr("\n"); } // print w/ spaces
template<class H, class... T> void ps(const H& h, const T&... t) { 
    pr(h); if (sizeof...(t)) pr(" "); ps(t...); }

// DEBUG
void DBG() { cerr << "]" << endl; }
template<class H, class... T> void DBG(H h, T... t) {
    cerr << ts(h); if (sizeof...(t)) cerr << ", ";
    DBG(t...); }
#ifdef LOCAL // compile with -DLOCAL, chk -> fake assert
    #define dbg(...) cerr << "Line(" << __LINE__ << ") -> [" << #__VA_ARGS__ << "]: [", DBG(__VA_ARGS__)
    #define chk(...) if (!(__VA_ARGS__)) cerr << "Line(" << __LINE__ << ") -> function(" \
         << __FUNCTION__  << ") -> CHK FAILED: (" << #__VA_ARGS__ << ")" << "\n", exit(0);
#else
    #define dbg(...) 0
    #define chk(...) 0
#endif

// FILE I/O
void setIn(str s) { freopen(s.c_str(),"r",stdin); }
void setOut(str s) { freopen(s.c_str(),"w",stdout); }
void unsyncIO() { cin.tie(0)->sync_with_stdio(0); }
void setIO(str s = "") {
    unsyncIO();
    // cin.exceptions(cin.failbit); 
    // throws exception when do smth illegal
    // ex. try to read letter into int
    if (sz(s)) { setIn(s+".in"), setOut(s+".out"); } // for USACO
}

ll gcd(ll a, ll b){
    a = abs(a); b = abs(b);
    if(a == 0) return b;
    if(b == 0) return a;
    return gcd(b%a, a);
}

const int mx = 2005;
int N;
int X[mx];
int Y[mx];
ll W[mx];
ll ans;



pl getBase(ll vx, ll vy, ll x, ll y){
    assert(vx != 0 || vy != 0);
    if(vy == 0){
        return getBase(vy, vx, y, x);
    }
    ll ey = ((y % vy) + vy) % vy;
    assert(0 <= ey && ey < vy);
    ll m = (ey-y)/vy;

    return mp(x+vx*m, y+vy*m);
}

struct Point {
    ll x, y;
    ll bx, by;
    Point(ll X, ll Y, ll px, ll py){
        assert(Y > 0 || (Y==0 && X > 0));
        ll g = gcd(X, Y);
        x = X/g;
        y = Y/g;
        pl base = getBase(x, y, px, py);
        bx = base.f;
        by = base.s;
    }
    bool operator<(const Point& r) const {
        if(x*r.y-y*r.x > 0) return 1;
        if(x*r.y-y*r.x < 0) return 0;
        return mp(bx, by) < mp(r.bx, r.by);
    }
    bool operator==(const Point& r){
        return mp(x, y) == mp(r.x, r.y);
    }
    bool operator!=(const Point &r){
        return mp(x, y) != mp(r.x, r.y);
    }
};

struct Node {
    ll maxsub, pref, suf, tot;
    Node(){
        maxsub = pref = suf = tot = 0;
    }
    Node(int val){
        maxsub = pref = suf = max(val, 0);
        tot = val;
    }
};

const Node ID = Node();

Node comb(Node a, Node b) {
    Node c = Node();
    c.maxsub = max(max(a.maxsub, b.maxsub), a.suf+b.pref);
    c.pref = max(a.pref, a.tot+b.pref);
    c.suf = max(b.suf, a.suf+b.tot);
    c.tot = a.tot+b.tot;
    return c;
} 
/**
 * Description: 1D point update, range query where \texttt{comb} is
    * any associative operation. If $N=2^p$ then \texttt{seg[1]==query(0,N-1)}.
 * Time: O(\log N)
 * Source: 
    * http://codeforces.com/blog/entry/18051
    * KACTL
 * Verification: SPOJ Fenwick
 */

template<class T> struct Seg { // comb(ID,b) = b
    int n; vector<T> seg;
    void init(int _n) { n = _n; seg.assign(2*n,ID); }
    void pull(int p) { seg[p] = comb(seg[2*p],seg[2*p+1]); }
    void upd(int p, int val) { // set val at position p
        seg[p += n] = Node(val); for (p /= 2; p; p /= 2) pull(p); }
    ll query() {    // sum on interval [l, r]
        return seg[1].maxsub;
    }
};

Seg<Node> seg;

int pos[mx]; //position of the ith point
int ipos[mx];



int main() {
    setIO();
    cin >> N;
    for(int i = 1; i <= N; i++){
        cin >> X[i] >> Y[i] >> W[i];
    }

    seg.init(2048);

    vector<pair<pi, int>> pints;
    for(int i = 1; i <= N; i++){
        pints.pb(mp(mp(Y[i], X[i]), i));
    }
    sort(all(pints));
    for(int i = 0; i < N; i++){
        pos[pints[i].s] = i+1;
        ipos[i+1] = pints[i].s; 
    }

    for(int i = 1; i <= N; i++){
        seg.upd(pos[i], W[i]);
        //dbg(pos[i], W[i]);
    }

    vector<pair<Point, pi>> upds;

    for(int i = 1; i <= N; i++){
        for(int j = i+1; j <= N; j++){
            int ind1 = i;
            int ind2 = j;
            if(Y[ind2]-Y[ind1] < 0 || (Y[ind2] == Y[ind1] && X[ind1] > X[ind2])){
                swap(ind1, ind2);
            }
            upds.pb(mp(Point(X[ind2]-X[ind1], Y[ind2]-Y[ind1], X[ind1], Y[ind2]), mp(ind1, ind2)));
        }
    }
    ckmax(ans, seg.query());
    sort(all(upds));

    for(int i = 0; i < sz(upds); i++){
        int k = i;
        for(int j = i; j < sz(upds); j++){
            if(upds[i].f == upds[j].f){
                k = j;
            }
            else break;
        }

       //maximum and minimum position for each group 
        for(int j = i; j <= k; j++){
            int maxh = j;
            pi minmax = mp(MOD, -MOD);
            for(int h = j; h <= k; h++){
                if(mp(upds[j].f.bx, upds[j].f.by) == mp(upds[h].f.bx, upds[h].f.by)){
                    int p1 = pos[upds[h].s.f];
                    int p2 = pos[upds[h].s.s];
                    ckmin(minmax.f, min(p1, p2));
                    ckmax(minmax.s, max(p1, p2));
                    maxh = h;
                }
                else break;
            }

            vpi linswap; //point index, new position 
            for(int j = minmax.f; j <= minmax.s; j++){
                linswap.pb(mp(ipos[j], minmax.f+minmax.s-j));
            }
            for(auto u: linswap){
                seg.upd(u.s, W[u.f]);
                pos[u.f] = u.s;
                ipos[u.s] = u.f;
            }
            j = maxh;
        }
        ckmax(ans, seg.query());
        i = k;
    }

    ps(ans);
    // you should actually read the stuff at the bottom
}

/* stuff you should look for
    * int overflow, array bounds
    * special cases (n=1?)
    * do smth instead of nothing and stay organized
    * WRITE STUFF DOWN
*/

Compilation message (stderr)

bulldozer.cpp: In function 'void setIn(str)':
bulldozer.cpp:168:28: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
  168 | void setIn(str s) { freopen(s.c_str(),"r",stdin); }
      |                     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~
bulldozer.cpp: In function 'void setOut(str)':
bulldozer.cpp:169:29: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
  169 | void setOut(str s) { freopen(s.c_str(),"w",stdout); }
      |                      ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~

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