Submission #1006278

#	Time	Username	Problem	Language	Result	Execution time	Memory
1006278		kebine	Bigger segments (IZhO19_segments)	C++17	0 / 100	3 ms	16988 KiB

segments

#include <bits/stdc++.h>
using namespace std;
#define pii pair<ll,ll>
#define REP(i,x,y) for(ll i=x;i<=y;i++)
#define freeopen   freopen("input.txt","r",stdin); freopen("output.txt","w",stdout);
#define mod 1000000000
#define pb push_back
#define mk make_pair
#define ll long long
#define foor(x,vec) for(auto x:vec ){cout<<x<<" ";}
#define fi first
#define se second
#define MAXN 500069
#define lld long double
#define cha ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
#define ffl fflush(stdout)
#define sst string
#define pii pair<ll,ll>
ll mvx[]={0,0,-1,1};
ll mvy[]={1,-1,0,0};

ll n;
ll a[MAXN],b[MAXN],ps[MAXN],dp[MAXN];
ll pos[MAXN],pos2[MAXN];
vector <ll> adj[MAXN];
map<ll,ll> mp;

void solve(){
    cin>>n;
    REP(i,1,n){
        cin>>a[i];
    }
    REP(i,1,n){
        ps[i]=ps[i-1]+a[i];
    }
    dp[1]=1;
    REP(i,1,n){
        ll lb=ps[i]+ps[pos[i]];
        ll l=pos[i];
        ll r=i;
        while(l<r){
            ll md=(l+r)>>1;
            if(2*ps[md]<=lb){
                r=md;
            }
            else{
                l=md+1;
            }
        }
        if(ps[i]-ps[r]>=ps[r]-ps[pos[i]]){
            dp[i]=dp[i-1]+1;
            pos[i]=max(r,pos[i-1]);
        }
        else{
            dp[i]=dp[i-1];
            pos[i]=pos[i-1];
        }
//        cout<<i<<" : "<<dp[i]<<" "<<pos[i]<<endl;
    }
    /*
     
     1 1 1 2 3
     0 0 0 2 4
     6 8 10 18 29
     ps[i]-ps[j]>=ps[j]-ps[pos[i]]
     ps[i]+ps[pos[i]]>=ps[j]
     
     */
    cout<<dp[n]<<endl;
}

int main(){
    ll tc;
    tc=1;
//    cin>>tc;
    while(tc--){
        solve();
    }
}

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