Submission #691449

#	Time	Username	Problem	Language	Result	Execution time	Memory
691449		drdilyor	Bigger segments (IZhO19_segments)	C++17	100 / 100	123 ms	27124 KiB

segments

#include <bits/stdc++.h>
#ifdef ONPC
    #include "t_debug.cpp"
#else
    #define debug(...) 42
#endif
using namespace std;
//namespace pbds = __gnu_pbds;
using ll = long long;
const int inf = 1e9;
const ll infl = 1e18;
const int RANDOM = chrono::high_resolution_clock::now().time_since_epoch().count();
mt19937 rng(RANDOM);
template<typename T, typename U> istream& operator>>(istream& is, pair<T, U>& p) { return is >> p.first >> p.second; }
template<typename Cont> int sz(const Cont& cont) { return int(cont.size()); }
const string fileio = "";
constexpr int tests = 0, nmax = 2e5, nlog = __lg(nmax), mod = 1e9+7;

int nextPower2(int n) {
    n--;
    n |= n >> 1;
    n |= n >> 2;
    n |= n >> 4;
    n |= n >> 8;
    n |= n >> 16;
    return 1+n;
}

struct SegTree {
    int n;
    vector<ll> tr;
    SegTree(int m) : n(nextPower2(m)), tr(n*2, infl) {}
    void update(int i, ll x) {
        tr[i+=n] = x;
        for (i /= 2; i >= 1; i /= 2) {
            tr[i] = min(tr[i*2], tr[i*2+1]);
        }
    }
    int query(ll x) {
        if (tr[1]> x) return -1;
        int v = 1;
        while (v < n) {
            if (tr[v*2+1]<= x) v = v* 2+1;
            else v =v *2;
        }
        return v - n;
    }
};

int solve() {
    int n; cin >> n;
    vector<int> arr(n);
    for (auto& i : arr) {cin >> i;}
    vector<ll> pref(n+1);
    for (int i = 0; i < n; i++)
        pref[i+1] = pref[i] + arr[i];

    vector<pair<int,ll>> dp(n+1);
    dp[0] = {1, 0};
    SegTree st(n+1);
    for (int i = 1; i <= n; i++) {
        dp[i] = {dp[i-1].first, dp[i-1].second - arr[i-1]};
        int j = st.query(pref[i]);
        if (j >= 0) {
            auto d = pair{dp[j].first+1, - (pref[i] - pref[j])};
            dp[i] = max(dp[i], d);
        }
        st.update(i, pref[i] - dp[i].second);
    }
    debug(dp);
    cout << dp[n].first << '\n';

    return 0;
}

signed main() {
    int t = 1;
    #ifdef ONPC
    t = 10000;
    #else
    if (fileio.size()) {freopen((fileio+".in").c_str(),"r",stdin);freopen((fileio+".out").c_str(),"w",stdout);}
    #endif
    cin.tie(0)->sync_with_stdio(0);
    cin.exceptions(cin.failbit | cin.eofbit);
    cout << fixed << setprecision(8);
    if (tests) cin >> t;
    while (t-- && cin) {
        if (solve()) break;
        #ifdef ONPC
            cout << "____________________" << endl;
        #endif
    }
    return 0;
}

/*
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▒███ ▒███  ▒███ ▒▒▒ ▒███ ▒███  ▒███  ▒███  ▒███ ▒███ ▒███ ▒███ ▒███ ▒▒▒ 
▒███ ▒███  ▒███     ▒███ ▒███  ▒███  ▒███  ▒███ ▒███ ▒███ ▒███ ▒███     
▒▒████████ █████    ▒▒████████ █████ █████ ▒▒███████ ▒▒██████  █████    
 ▒▒▒▒▒▒▒▒ ▒▒▒▒▒      ▒▒▒▒▒▒▒▒ ▒▒▒▒▒ ▒▒▒▒▒   ▒▒▒▒▒███  ▒▒▒▒▒▒  ▒▒▒▒▒     
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*/

Compilation message (stderr)

segments.cpp: In function 'int solve()':
segments.cpp:5:24: warning: statement has no effect [-Wunused-value]
    5 |     #define debug(...) 42
      |                        ^~
segments.cpp:70:5: note: in expansion of macro 'debug'
   70 |     debug(dp);
      |     ^~~~~
segments.cpp: In function 'int main()':
segments.cpp:81:32: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   81 |     if (fileio.size()) {freopen((fileio+".in").c_str(),"r",stdin);freopen((fileio+".out").c_str(),"w",stdout);}
      |                         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
segments.cpp:81:74: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   81 |     if (fileio.size()) {freopen((fileio+".in").c_str(),"r",stdin);freopen((fileio+".out").c_str(),"w",stdout);}
      |                                                                   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 13 / 13
• Subtask 2: 14 / 14
• Subtask 3: 10 / 10
• Subtask 4: 36 / 36
• Subtask 5: 27 / 27