Submission #1091943

#	Time	Username	Problem	Language	Result	Execution time	Memory
1091943		anhthi	Divide and conquer (IZhO14_divide)	C++14	100 / 100	40 ms	8392 KiB

divide

#include <bits/stdc++.h>

using namespace std;

#define fi first
#define se second
#define ll long long
#define mp(x, y) make_pair(x, y)
#define sz(v) ((int) (v).size())
#define all(v) (v).begin(), (v).end()
#define MASK(i) (1LL << (i))
#define BIT(x, y) (((x) >> (y)) & 1)
#define pb push_back
#define max_rng *max_element
#define min_rng *min_element
#define rep(i, n) for(int i = 1, _n = (n); i <= _n; ++i)
#define forn(i, a, b) for(int i = (a), _b = (b); i <= _b; ++i)
#define ford(i, a, b) for(int i = (a), _b = (b); i >= _b; --i)

template <class X, class Y>
    inline bool maximize(X &x, Y y) {
        return (x < y ? x = y, true : false);
    }

template <class X, class Y>
    inline bool minimize(X &x, Y y) {
        return (x > y ? x = y, true : false);
    }

template <class X>
    inline void compress(vector<X> &a) {
        sort(all(a));
        a.resize(unique(all(a)) - a.begin());
    }

int ctz(ll x) { return __builtin_ctzll(x); }
int lg(ll x) { return 63 - __builtin_clzll(x); }
int popcount(ll x) { return __builtin_popcount(x); }

mt19937_64 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
ll rand(ll l, ll r) {
    return l + abs((ll) rng()) % (r - l + 1);
}

const ll oo = (ll) 1e17;
const int inf = (ll) 2e9 + 7, mod = (ll) 1e9 + 7;

const int mxn = 2e5 + 5;

void add(int &x, int y) { x += y; if (x >= mod) x -= mod; }
void sub(int &x, int y) { x -= y; if (x < 0) x += mod; }

int n;
struct Mine {
    int x, g, d;
    void input() {
        cin >> x >> g >> d;
    }
} mine[mxn];
ll pref[mxn], cost[mxn];

struct fen {
    int n;
    vector<int> b;
    fen(int n) : n(n) {
        b.resize(n + 5);
    }
    void upd(int p, int d) {
        for (; p <= n; p += p & -p)
            maximize(b[p], d);
        return;
    }
    int get(int p) {
        int ans = 0;
        for (; p > 0; p -= p & -p)
            maximize(ans, b[p]);

        return ans;
    }
};

int main(void) {

    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);

    #define TASK "tsk"
    if (fopen(TASK".inp", "r")) {
        freopen(TASK".inp", "r", stdin);
        freopen(TASK".out", "w", stdout);
    }

    cin >> n;
    rep(i, n) {
        mine[i].input();
        pref[i] = pref[i-1] + mine[i].d;
        cost[i] = cost[i-1] + mine[i].g;
    }

    vector<ll> cps;
    rep(i, n) {
        cps.pb(mine[i].x - pref[i]);
        cps.pb(mine[i].x - pref[i - 1]);
    }

    compress(cps);

    fen f(sz(cps));
    ll ans = 0;
    ford(i, n, 1) {
        f.upd(lower_bound(all(cps), mine[i].x - pref[i]) - cps.begin() + 1, i);
        int pos = lower_bound(all(cps), mine[i].x - pref[i - 1]) - cps.begin() + 1;
        int res = f.get(pos);
        if (res) maximize(ans, cost[res] - cost[i - 1]);
    }

    cout << ans;

    return 0;
}

Compilation message (stderr)

divide.cpp: In function 'int main()':
divide.cpp:89:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   89 |         freopen(TASK".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
divide.cpp:90:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   90 |         freopen(TASK".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 17 / 17
• Subtask 2: 31 / 31
• Subtask 3: 52 / 52