Submission #580442

#	Time	Username	Problem	Language	Result	Execution time	Memory
580442		thezomb1e	Divide and conquer (IZhO14_divide)	C++17	100 / 100	191 ms	67620 KiB

divide

//thatsramen
 
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
 
#define eb emplace_back
#define pb push_back
#define ft first
#define sd second
#define pi pair<ll, ll>
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define dbg(...) dbg_out(__VA_ARGS__)
 
using ll = long long;
using ld = long double;
using namespace std;
using namespace __gnu_pbds;
 
//Constants
const ll INF = 5 * 1e18;
const int IINF = 2 * 1e9;
const ll MOD = 1e9 + 7;
// const ll MOD = 998244353;
const ll dx[4] = {1, 0, -1, 0}, dy[4] = {0, 1, 0, -1};
const ld PI = 3.14159265359;
 
//Templates
template<typename A, typename B> ostream& operator<<(ostream &os, const pair<A, B> &p) {return os << '(' << p.first << ", " << p.second << ')';}
template<typename T_container, typename T = typename enable_if<!is_same<T_container, string>::value, typename T_container::value_type>::type> ostream& operator<<(ostream &os, const T_container &v) {os << '['; string sep; for (const T &x : v) os << sep << x, sep = ", "; return os << ']';}
void dbg_out() {cerr << endl;}
template<typename Head, typename... Tail> void dbg_out(Head H, Tail... T) { cerr << H << ' '; dbg_out(T...); }
template<typename T> void mins(T& x, T y) {x = min(x, y);}
template<typename T> void maxs(T& x, T y) {x = max(x, y);}
template<typename T> using oset = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
template<typename T> using omset = tree<T, null_type, less_equal<T>, rb_tree_tag, tree_order_statistics_node_update>;
 
//order_of_key(k): number of elements strictly less than k
//find_by_order(k): k-th element in the set
 
void setPrec() {cout << fixed << setprecision(15);}
void unsyncIO() {cin.tie(0)->sync_with_stdio(0);}
void setIn(string s) {freopen(s.c_str(), "r", stdin);}
void setOut(string s) {freopen(s.c_str(), "w", stdout);}
void setIO(string s = "") {
    unsyncIO(); setPrec();
    if(s.size()) setIn(s + ".in"), setOut(s + ".out");
}
 
// #define TEST_CASES

struct SegmentTree {

    struct Node {
        vector<pi> ar;
        vector<ll> suf;
    };
    
    vector<Node> tre;
    int sz;
    
    SegmentTree(vector<pi> &a) {
        int n = (int) a.size();
        sz = 1;
        while (sz < n) sz *= 2;
        tre.resize(2 * sz);
        build(a, 1, 0, sz);
    }

    void rcl(int x) {
        int p_l = 0, p_r = 0,
            sz_l = tre[2 * x].ar.size(), 
            sz_r = tre[2 * x + 1].ar.size();
        while ((p_l < sz_l) || (p_r < sz_r)) {
            if (p_r == sz_r || (p_l < sz_l && tre[2 * x].ar[p_l].ft < tre[2 * x + 1].ar[p_r].ft)) {
                tre[x].ar.pb(tre[2 * x].ar[p_l]);
                p_l++;
            } else {
                tre[x].ar.pb(tre[2 * x + 1].ar[p_r]);
                p_r++;
            }
        }
        int sz_cur = sz_l + sz_r;
        tre[x].suf.resize(sz_cur);
        for (int i = sz_cur - 1; i >= 0; i--) {
            tre[x].suf[i] = tre[x].ar[i].sd;
            if (i != sz_cur - 1)
                maxs(tre[x].suf[i], tre[x].suf[i + 1]);
        }
    }

    void build(vector<pi> &a, int x, int lx, int rx) {
        if (rx - lx == 1) {
            if (lx < a.size()) {
                tre[x].ar.pb(a[lx]);
                tre[x].suf.pb(a[lx].sd);
            }
            return;
        }
        int m = (lx + rx) / 2;
        build(a, 2 * x, lx, m);
        build(a, 2 * x + 1, m, rx);
        rcl(x);
    }

    ll get(int l, int r, ll bb, int x, int lx, int rx) {
        if (rx <= l || lx >= r) {
            return -INF;
        }
        if (l <= lx && r >= rx) {
            pi comp = {bb, -INF};
            int j = lower_bound(all(tre[x].ar), comp) - tre[x].ar.begin();
            if (j == (int) tre[x].ar.size()) return -INF;
            return tre[x].suf[j];
        }
        int m = (lx + rx) / 2;
        ll s1 = get(l, r, bb, 2 * x, lx, m);
        ll s2 = get(l, r, bb, 2 * x + 1, m, rx);
        return max(s1, s2);
    }

    ll get(int l, int r, ll bb) {
        return get(l, r, bb, 1, 0, sz);
    }
};
 
void solve() {
    int n;
    cin >> n;
    vector<int> x(n), g(n), d(n);
    for (int i = 0; i < n; i++) {
        cin >> x[i] >> g[i] >> d[i];
    }
    vector<pi> init(n);
    {
        ll pref_gold = 0, pref_energy = 0;
        for (int i = 0; i < n; i++) {
            ll len = x[i] - x[0];
            init[i] = {len - pref_energy, pref_gold};
            pref_energy += d[i];
            pref_gold -= g[i];
        }
    }
    SegmentTree st(init);
    ll pref_gold = 0, pref_energy = 0, ans = 0;
    for (int i = 0; i < n; i++) {
        ll len = x[i] - x[0];
        pref_energy += d[i]; pref_gold += g[i];
        ll bb = len - pref_energy;
        ll res = pref_gold + st.get(0, i + 1, bb);
        maxs(ans, res);
    }
    cout << ans;
}
 
int main() {
    setIO();
 
    int tt = 1;
    #ifdef TEST_CASES
        cin >> tt;
    #endif
 
    while (tt--)
        solve();
 
    return 0;
}

Compilation message (stderr)

divide.cpp: In member function 'void SegmentTree::build(std::vector<std::pair<long long int, long long int> >&, int, int, int)':
divide.cpp:95:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<long long int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   95 |             if (lx < a.size()) {
      |                 ~~~^~~~~~~~~~
divide.cpp: In function 'void setIn(std::string)':
divide.cpp:44:30: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   44 | void setIn(string s) {freopen(s.c_str(), "r", stdin);}
      |                       ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
divide.cpp: In function 'void setOut(std::string)':
divide.cpp:45:31: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   45 | void setOut(string s) {freopen(s.c_str(), "w", stdout);}
      |                        ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

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