제출 #744188

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
744188		onebit1024	Bigger segments (IZhO19_segments)	C++17	13 / 100	2 ms	348 KiB

segments

#include <bits/stdc++.h>
using namespace std;

#define int long long
#define pb push_back
#define all(c) c.begin(), c.end()
#define endl "\n"

const double PI=3.141592653589;


void __print(int x) {cerr << x;}
void __print(long x) {cerr << x;}
void __print(unsigned x) {cerr << x;}
void __print(unsigned long x) {cerr << x;}
void __print(unsigned long long x) {cerr << x;}
void __print(float x) {cerr << x;}
void __print(double x) {cerr << x;}
void __print(long double x) {cerr << x;}
void __print(char x) {cerr << '\'' << x << '\'';}
void __print(const char *x) {cerr << '\"' << x << '\"';}
void __print(const string &x) {cerr << '\"' << x << '\"';}
void __print(bool x) {cerr << (x ? "true" : "false");}

template<typename T, typename V>
void __print(const pair<T, V> &x) {cerr << '{'; __print(x.first); cerr << ','; __print(x.second); cerr << '}';}
template<typename T>
void __print(const T &x) {int f = 0; cerr << '{'; for (auto &i: x) cerr << (f++ ? "," : ""), __print(i); cerr << "}";}
void _print() {cerr << "]\n";}
template <typename T, typename... V>
void _print(T t, V... v) {__print(t); if (sizeof...(v)) cerr << ", "; _print(v...);}
#ifndef ONLINE_JUDGE
#define dbg(x...) cerr << "LINE(" << __LINE__ << ") -> " <<"[" << #x << "] = ["; _print(x)
#else
#define dbg(x...)
#endif

int n;
vector<int>a,pref;

int f(int x){
    vector<pair<int,int>>dp(n+1);
    int pos = 0;
    for(int i = 1;i<=n;++i){
        dp[i].second = dp[i-1].second+a[i];
        if(dp[i].second >= x){
            pos = i;
            dp[i].first = 1;
            break;
        }
    }
    if(pos==0)return 0;
    // pos denotes starting position of maxdp value so far
    vector<pair<int,int>>p;
    for(int i = pos+1;i<=n;++i){
        int l = pos, r = i-1;
        bool got = 0;
        dp[i] = {dp[i-1].first,dp[i-1].second+a[i]};

        while(l <= r){
            int m = (l+r)/2;
            if(pref[i]-pref[m] >= dp[m].second){
                l = m+1;
                got = 1;
                dp[i].first = dp[pos].first+1;
                dp[i].second = pref[i]-pref[m];
            }else r = m-1;
        }
        if(got){
            p.pb({pos,i-1});
            pos = i;
            continue;
        }
        if(p.empty())continue;
        // can't increase segment size, so try to reduce sum of current segment
        l = p.back().first, r = p.back().second;
        while(l <= r){
            int m = (l+r)/2;
            if(pref[i]-pref[m] >= dp[m].second){
                l = m+1;
                dp[i].second = min(dp[i].second,pref[i]-pref[m]);
            }else r = m-1;
        }
    }
    return dp[n].first;
}
void solve()
{
    cin >> n;
    a.resize(n+1);
    pref.resize(n+1);
    for(int i = 1;i<=n;++i)cin >> a[i];
    for(int i = 1;i<=n;++i)pref[i] = pref[i-1]+a[i];
    int l = 1, r = 1e18;
    while(l+2 < r){
        int m1 = (l+(r-l)/3), m2 = (r-(r-l)/3);
        if(f(m1) < f(m2))l = m1;
        else r = m2;
    }
    
    int res = 0;
    for(int i = l;i<=r;++i)res = max(res, f(i));
    cout << res << endl;
}   

int32_t main()
{

    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);


    // freopen("input.txt", "r", stdin);
    // freopen("output.txt", "w", stdout);
    

    int T=1;
    for(int i = 1;i<=T;++i)
    {
        // cout << "Case #" << i << ": ";
        solve();
    }
}

• Subtask 1: 13 / 13
• Subtask 2: 0 / 14
• Subtask 3: 0 / 10
• Subtask 4: 0 / 36
• Subtask 5: 0 / 27