제출 #1249083

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1249083		al95ireyiz	Bigger segments (IZhO19_segments)	C++20	100 / 100	1241 ms	24304 KiB

segments

//*** Bismillah ***//
#pragma GCC optimize("O3", "fast-math", "unroll-loops", "no-stack-protector")
#include <bits/stdc++.h>
using namespace std;
#if !defined(ONLINE_JUDGE) and !defined(EVAL)
#include "template/debug.h"
#else
#define d(x...)
#endif
#define fr first
#define er erase
#define sc second
#define in insert
#define ll long long
#define pb push_back
#define vll vector<ll>
#define pll pair<ll,ll>
#define ull unsigned ll
#define vpll vector<pll>
#define len(x) (ll) x.size()
#define all(x) x.begin(),x.end()
const ll INF = 1e9;
const ll INFL = 1e18;
const ll MOD = 1e9+7;
// const ll MOD = 998244353;
const ll maxn = 5e5+5;
ll n,m,k=0;
ll a[maxn], ps[maxn], dp[maxn], mn[maxn], tree[4 * maxn];
void upd(ll x, ll val, ll l = 1, ll r = n + 1, ll v = 1){
    if(l == r){
        tree[v] = val;
        return;
    }
    ll md = (l + r) >> 1;
    if(x <= md) upd(x, val, l, md, v << 1);
    else upd(x, val, md + 1, r, v << 1 | 1);
    tree[v] = min(tree[v << 1], tree[v << 1 | 1]);
}
ll get(ll _l, ll _r, ll l = 1, ll r = n + 1, ll v = 1){
    bool in = _l <= l and r <= _r;
    bool ot = _l <= r and l <= _r;
    if(in) return tree[v];
    if(ot){
        ll md = (l + r) >> 1;
        return min(
            get(_l, _r, l, md, v << 1),
            get(_l, _r, md + 1, r, v << 1 | 1)
        );
    }
    return INFL;
}
void _(ll &tt){
    cin >> n;
    for(ll i = 1; i <= n; i ++){
        cin >> a[i];
        mn[i] = INFL;
        ps[i] = ps[i - 1] + a[i];
    }
    mn[0] = 0;
    upd(1, 0);
    for(ll i = 1; i <= n; i ++){
        // for(ll j = i - 1; j >= 0; j --){
        //     if(mn[j] <= ps[i] - ps[j]){
        //         if(dp[i] < dp[j] + 1){
        //             dp[i] = dp[j] + 1;
        //             mn[i] = ps[i] - ps[j];
        //         }
        //         else if(dp[i] == dp[j] + 1){
        //             mn[i] = min(mn[i], ps[i] - ps[j]);
        //         }
        //         break;
        //     }
        // }
        // bs for last j that mn[j] <= ps[i] - ps[j]
        // mn[j] + ps[j] <= ps[i]
        ll l = 0, r = i - 1, j;
        while(l <= r){
            ll md = (l + r) >> 1;
            if(get(md + 1, i - 1 + 1) <= ps[i]) l = md + 1, j = md;
            else r = md - 1;
        }
        if(mn[j] <= ps[i] - ps[j]){
            if(dp[i] < dp[j] + 1){
                dp[i] = dp[j] + 1;
                mn[i] = ps[i] - ps[j];
            }
            else if(dp[i] == dp[j] + 1){
                mn[i] = min(mn[i], ps[i] - ps[j]);
            }
        }
        upd(i + 1, ps[i] + mn[i]);
    }
    // for(ll i = 1; i <= n; i ++) cout << dp[i] << ' '; cout << '\n';
    // for(ll i = 1; i <= n; i ++) cout << mn[i] << ' '; cout << '\n';
    // for(ll i = 1; i <= n; i ++) cout << ps[i] + mn[i] << ' '; cout << '\n';
    cout << dp[n] << '\n';
}
signed main() {
    ll tm = clock();
    cin.tie(0)->sync_with_stdio(0);
    ll t = 1;
    // cin >> t;
    for(ll tt = 1; tt <= t; tt ++) {
        _(tt);
    }
    cerr << "\n\033[1;31mTime: \033[1;30m" \
         << (double)(clock()-tm)/1000000 << "\033[1;32m seconds\n";
}

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