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Submission #1019353

# Submission time Handle Problem Language Result Execution time Memory
1019353 2024-07-10T18:12:06 Z DobromirAngelov Fancy Fence (CEOI20_fancyfence) C++14
100 / 100
 34 ms 7260 KB 
#include<bits/stdc++.h>
#define endl '\n'
#define fi first
#define se second
#define int long long

using namespace std;

const int MAXN=1e5+5;
const int MOD=1e9+7;
const int INV2SQ=250000002;

int n;
int h[MAXN];
int w[MAXN];
long long pref[MAXN];
int ord[MAXN];
bool used[MAXN];
vector<pair<int,int> > ev;
pair<int,int> rng[MAXN];
int ans=0;

int rect(long long w,long long h)
{
    w%=MOD;
    h%=MOD;
    return (((w*(w+1))%MOD)*((h*(h+1))%MOD)%MOD*INV2SQ)%MOD;
}

void sum(int &a,int val)
{
    a+=val;
    if(a>=MOD) a-=MOD;
}

void subtr(int &a,int val)
{
    a-=val;
    if(a<0) a+=MOD;
}

void addL(int ind)
{
    ev.push_back({rng[ind-1].fi, ind});
    long long d=pref[ind-1]-pref[rng[ind-1].fi-1];
    subtr(ans, rect(d,h[ind]));
}

void changeRngL(int ind)
{
    int l=rng[ind-1].fi;
    int r=rng[ind].se;
    rng[l]={rng[l].fi, rng[r].se};
    rng[r]={rng[l].fi, rng[r].se};
}

void addR(int ind)
{
    ev.push_back({ind, rng[ind+1].se});
    long long d=pref[rng[ind+1].se]-pref[ind];
    subtr(ans, rect(d,h[ind]));
}

void changeRngR(int ind)
{
    int l=rng[ind].fi;
    int r=rng[ind+1].se;
    rng[l]={rng[l].fi, rng[r].se};
    rng[r]={rng[l].fi, rng[r].se};
}

void calc(int h)
{
    for(auto cur: ev)
    {//cout<<"("<<cur.fi<<","<<cur.se<<")  ";
        long long d=pref[cur.se]-pref[cur.fi-1];
        sum(ans, rect(d,h));
        //cout<<1/0<<endl;
    }
    ev.clear();
    //cout<<ans<<endl;
}

bool cmp(int x,int y)
{
    if(h[x]==h[y]) return x<y;
    return h[x]>h[y];
}

signed main()
{
ios::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);

cin>>n;
for(int i=1;i<=n;i++) cin>>h[i];
for(int i=1;i<=n;i++) cin>>w[i];

for(int i=1;i<=n;i++) pref[i]=pref[i-1]+w[i];
for(int i=1;i<=n;i++) rng[i]={i,i};

iota(ord,ord+n,1);
sort(ord,ord+n,cmp);

for(int i=0;i<n;i++)
{
    if(i>0 && h[ord[i]]<h[ord[i-1]]) calc(h[ord[i-1]]);

    int ind=ord[i];

    pair<int,int> last({-1,-1});
    if(!ev.empty()) last=ev.back();

    if(used[ind-1])
    {//cout<<i<<" "<<ind<<" "<<last.fi<<" "<<last.se<<endl;
        if(ind-1==last.se) last.se++, ev.back().se++;
        else addL(ind);
        changeRngL(ind);
        //cout<<ans<<" "<<rng[ind].fi<<" "<<rng[ind].se<<endl;
    }
    if(ev.size()>0) last=ev.back();
    if(used[ind+1])
    {//cout<<i<<" "<<ind<<" "<<last.fi<<" "<<last.se<<endl;
        if(last.se==ind)
        {
            last.se=rng[ind+1].se; ev.back().se=rng[ind+1].se;
            long long d=pref[rng[ind+1].se]-pref[ind];
            subtr(ans, rect(d,h[ind]));
        }
        else addR(ind);
        changeRngR(ind);
        //cout<<ans<<" "<<rng[ind].fi<<" "<<rng[ind].se<<endl;
    }

    if(!used[ind-1] && !used[ind+1]) sum(ans, rect(w[ind], h[ind]));

    used[ind]=1;

    //cout<<i<<" "<<ord[i]<<": "<<ans<<endl;
}
calc(h[ord[n-1]]);

cout<<ans<<endl;

return 0;
}
/*
6
1 3 5 3 2 6
1 1 1 1 1 1

5
1 3 5 3 2
3 2 1 3 3

7
3 4 1 9 8 3 9
1 1 1 1 1 1 1

10
4 4 4 4 4 4 4 4 4 4
1 3 7 8 4 5 9 2 7 5

17
5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5
2 3 9 5 7 3 8 1 9 9 6 1 2 4 8 5 4

*/

Subtask #1
0.0 / 0.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 4444 KB Output is correct
2 Correct 1 ms 4444 KB Output is correct

Subtask #2
12.0 / 12.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 4440 KB Output is correct
2 Correct 1 ms 4564 KB Output is correct
3 Correct 1 ms 4444 KB Output is correct
4 Correct 1 ms 4444 KB Output is correct
5 Correct 1 ms 4440 KB Output is correct

Subtask #3
13.0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 4444 KB Output is correct
2 Correct 1 ms 4444 KB Output is correct
3 Correct 10 ms 5460 KB Output is correct
4 Correct 21 ms 6480 KB Output is correct
5 Correct 21 ms 6748 KB Output is correct
6 Correct 19 ms 6492 KB Output is correct

Subtask #4
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 4444 KB Output is correct
2 Correct 3 ms 4700 KB Output is correct
3 Correct 10 ms 5832 KB Output is correct
4 Correct 20 ms 6988 KB Output is correct
5 Correct 19 ms 7260 KB Output is correct
6 Correct 1 ms 4444 KB Output is correct

Subtask #5
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 4444 KB Output is correct
2 Correct 1 ms 4444 KB Output is correct
3 Correct 2 ms 4696 KB Output is correct
4 Correct 12 ms 5720 KB Output is correct
5 Correct 22 ms 6980 KB Output is correct
6 Correct 30 ms 7260 KB Output is correct
7 Correct 1 ms 4440 KB Output is correct
8 Correct 3 ms 4836 KB Output is correct
9 Correct 11 ms 5724 KB Output is correct
10 Correct 20 ms 7004 KB Output is correct
11 Correct 21 ms 7000 KB Output is correct
12 Correct 1 ms 4444 KB Output is correct

Subtask #6
18.0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 4444 KB Output is correct
2 Correct 1 ms 4444 KB Output is correct
3 Correct 1 ms 4444 KB Output is correct
4 Correct 1 ms 4444 KB Output is correct
5 Correct 1 ms 4444 KB Output is correct
6 Correct 1 ms 4564 KB Output is correct
7 Correct 1 ms 4444 KB Output is correct
8 Correct 1 ms 4472 KB Output is correct
9 Correct 1 ms 4444 KB Output is correct
10 Correct 2 ms 4440 KB Output is correct
11 Correct 1 ms 4444 KB Output is correct
12 Correct 1 ms 4444 KB Output is correct
13 Correct 1 ms 4576 KB Output is correct
14 Correct 1 ms 4444 KB Output is correct
15 Correct 1 ms 4580 KB Output is correct
16 Correct 1 ms 4444 KB Output is correct

Subtask #7
27.0 / 27.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 4444 KB Output is correct
2 Correct 1 ms 4444 KB Output is correct
3 Correct 1 ms 4700 KB Output is correct
4 Correct 1 ms 4576 KB Output is correct
5 Correct 1 ms 4440 KB Output is correct
6 Correct 1 ms 4444 KB Output is correct
7 Correct 1 ms 4444 KB Output is correct
8 Correct 1 ms 4444 KB Output is correct
9 Correct 1 ms 4444 KB Output is correct
10 Correct 1 ms 4444 KB Output is correct
11 Correct 10 ms 5456 KB Output is correct
12 Correct 21 ms 6408 KB Output is correct
13 Correct 22 ms 6748 KB Output is correct
14 Correct 19 ms 6488 KB Output is correct
15 Correct 1 ms 4440 KB Output is correct
16 Correct 3 ms 4700 KB Output is correct
17 Correct 10 ms 5704 KB Output is correct
18 Correct 26 ms 7004 KB Output is correct
19 Correct 21 ms 7256 KB Output is correct
20 Correct 1 ms 4440 KB Output is correct
21 Correct 2 ms 4700 KB Output is correct
22 Correct 11 ms 5704 KB Output is correct
23 Correct 21 ms 6988 KB Output is correct
24 Correct 20 ms 7180 KB Output is correct
25 Correct 1 ms 4444 KB Output is correct
26 Correct 1 ms 4444 KB Output is correct
27 Correct 1 ms 4444 KB Output is correct
28 Correct 1 ms 4444 KB Output is correct
29 Correct 1 ms 4444 KB Output is correct
30 Correct 3 ms 4700 KB Output is correct
31 Correct 4 ms 4836 KB Output is correct
32 Correct 15 ms 5724 KB Output is correct
33 Correct 15 ms 5704 KB Output is correct
34 Correct 28 ms 7000 KB Output is correct
35 Correct 34 ms 6984 KB Output is correct
36 Correct 29 ms 7004 KB Output is correct
37 Correct 29 ms 7000 KB Output is correct
38 Correct 1 ms 4444 KB Output is correct
39 Correct 29 ms 7196 KB Output is correct
40 Correct 26 ms 7004 KB Output is correct
41 Correct 25 ms 7004 KB Output is correct
42 Correct 26 ms 7004 KB Output is correct