Submission #919098

#	Time	Username	Problem	Language	Result	Execution time	Memory
919098		Whisper	Bigger segments (IZhO19_segments)	C++17	100 / 100	64 ms	26568 KiB

segments

#include <bits/stdc++.h>

using namespace std;
using ll = long long;
using ld = long double;
using T = tuple<ll, ll, ll>;

#define int long long
#define Base 41
#define sz(a) (int)a.size()
#define FOR(i, a, b) for ( int i = a ; i <= b ; i++ )
#define FORD(i, a, b) for (int i = b; i >= a; i --)
#define REP(i, n) for (int i = 0; i < n; ++i)
#define REPD(i, n) for (int i = n - 1; i >= 0; --i)
#define all(x) x.begin() , x.end()
#define pii pair<int , int>
#define fi first
#define se second
#define Lg(x) 31 - __builtin_clz(x)

#define MASK(i) (1LL << (i))
#define BIT(x, i) (((x) >> (i)) & 1)

constexpr ll LINF = (1ll << 60);
constexpr int INF = (1ll << 30);
constexpr int MAX = 5e5 + 5;
constexpr int Mod = 1e9 + 7;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

void setupIO(){
    #define name "Whisper"
    //Phu Trong from Nguyen Tat Thanh High School for gifted student
    srand(time(NULL));
    cin.tie(nullptr)->sync_with_stdio(false); cout.tie(nullptr);
    //freopen(name".inp", "r", stdin);
    //freopen(name".out", "w", stdout);
    cout << fixed << setprecision(10);
}

template <class X, class Y>
    bool minimize(X &x, const Y &y){
        X eps = 1e-9;
        if (x > y + eps) {x = y; return 1;}
        return 0;
    }

template <class X, class Y>
    bool maximize(X &x, const Y &y){
        X eps = 1e-9;
        if (x + eps < y) {x = y; return 1;}
        return 0;
    }

int N;
int a[MAX];
pii dp[MAX];
int s[MAX];
vector<int> best;
void Add(int x){
    while (best.size() && dp[best.back()].se + s[best.back()] >= dp[x].se + s[x]){
        best.pop_back();
    }
    best.push_back(x);
}
void Whisper(){
    cin >> N;
    for (int i = 1; i <= N; ++i) cin >> a[i], s[i] = s[i - 1] + a[i];
    //s(i) - s(j) >= s(j) - s(x)
    //-> s(i) >= 2 * s(j) - s(x)

    Add(0);
    for (int i = 1; i <= N; ++i){
        int l = 0, r = sz(best) - 1;
        while (l <= r){
            int mid = (l + r) >> 1;
            int x = best[mid];
            if (s[i] >= s[x] + dp[x].se){
                dp[i].fi = dp[x].fi + 1;
                dp[i].se = (s[i] - s[x]);
                l = mid + 1;
            }
            else r = mid - 1;
        }
        Add(i);
    }
    cout << dp[N].fi;
}


signed main(){
    setupIO();
    int Test = 1;
//    cin >> Test;
    for ( int i = 1 ; i <= Test ; i++ ){
        Whisper();
        if (i < Test) cout << '\n';
    }
}

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