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Submission #289502

# Submission time Handle Problem Language Result Execution time Memory
289502 2020-09-02T17:18:52 Z model_code Fancy Fence (CEOI20_fancyfence) C++17
100 / 100
 44 ms 2972 KB 
#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

/*
A not too simple solution:
Sort sections in decreasing order by height
Use DSU (why not?, it's a good practice) when merging intervals
Note that you don't need so many long long, i just wanted to be sure
Note that this is an O(NlogN) solution because of the sorting

Made for you by Mate Busa
*/

const long long mod = 1000000007;
long long N, ans;
long long h[100000];
long long w[100000];
vector<int> sections;
int parent[100000];
bool done[100000];

//calculate binom(x,2)
long long bin(long long x){
	x %= mod;
    return ((x*(x+1))/2)%mod;
}
//count fancy rectangles in a big rectangle of size x*y
long long rec(long long x, long long y){
    return (bin(x)*bin(y))%mod;
}

//DSU
int find_set(int x){
    if(parent[x]<0) return x;
    return (parent[x] = find_set(parent[x]));
}
void union_sets(int x, int y, long long high){
    x = find_set(x); y = find_set(y);
    long long h = (rec(w[x],high)+rec(w[y],high))%mod;
    h = (rec(w[x]+w[y],high)-h+mod)%mod; ans = (ans+h)%mod;
    if(parent[x]<parent[y]){
        parent[y] = x;
        w[x] = (w[x]+w[y])%mod;
    } else {
        if(parent[x]==parent[y]) parent[y]--;
        parent[x] = y;
        w[y] = (w[x]+w[y])%mod;
    }
}

bool smaller(int x, int y){
    return h[x]>h[y];
}

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(0); cout.tie(0);

    cin >> N;

    for(int i=0; i<N; i++){
        cin >> h[i];
        sections.push_back(i); parent[i] = -1;
    }
    for(int i=0; i<N; i++) cin >> w[i];
    //sort sections by height
    sort(sections.begin(),sections.end(),smaller);

    for(int i=0; i<N; i++) ans = (ans+rec(w[i],h[i]))%mod;

    for(int i:sections){
        //merge intervals
        if(i!=0 && done[i-1]) union_sets(i-1,i,h[i]);
        if(i!=N-1 && done[i+1]) union_sets(i,i+1,h[i]);
        done[i] = true;
    }

    cout << ans << '\n';

    return 0;
}

Subtask #1
0.0 / 0.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 384 KB Output is correct
2 Correct 1 ms 384 KB Output is correct

Subtask #2
12.0 / 12.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 384 KB Output is correct
2 Correct 0 ms 384 KB Output is correct
3 Correct 1 ms 384 KB Output is correct
4 Correct 1 ms 288 KB Output is correct
5 Correct 1 ms 384 KB Output is correct

Subtask #3
13.0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 384 KB Output is correct
2 Correct 1 ms 384 KB Output is correct
3 Correct 14 ms 1664 KB Output is correct
4 Correct 29 ms 2940 KB Output is correct
5 Correct 34 ms 2928 KB Output is correct
6 Correct 29 ms 2908 KB Output is correct

Subtask #4
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 384 KB Output is correct
2 Correct 4 ms 640 KB Output is correct
3 Correct 17 ms 1664 KB Output is correct
4 Correct 33 ms 2940 KB Output is correct
5 Correct 35 ms 2932 KB Output is correct
6 Correct 1 ms 384 KB Output is correct

Subtask #5
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 384 KB Output is correct
2 Correct 1 ms 384 KB Output is correct
3 Correct 4 ms 640 KB Output is correct
4 Correct 16 ms 1664 KB Output is correct
5 Correct 37 ms 2932 KB Output is correct
6 Correct 36 ms 2928 KB Output is correct
7 Correct 1 ms 384 KB Output is correct
8 Correct 4 ms 640 KB Output is correct
9 Correct 17 ms 1664 KB Output is correct
10 Correct 35 ms 2940 KB Output is correct
11 Correct 33 ms 2940 KB Output is correct
12 Correct 0 ms 384 KB Output is correct

Subtask #6
18.0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 384 KB Output is correct
2 Correct 1 ms 384 KB Output is correct
3 Correct 1 ms 384 KB Output is correct
4 Correct 0 ms 384 KB Output is correct
5 Correct 1 ms 384 KB Output is correct
6 Correct 1 ms 384 KB Output is correct
7 Correct 1 ms 384 KB Output is correct
8 Correct 1 ms 384 KB Output is correct
9 Correct 1 ms 384 KB Output is correct
10 Correct 1 ms 384 KB Output is correct
11 Correct 0 ms 384 KB Output is correct
12 Correct 1 ms 384 KB Output is correct
13 Correct 1 ms 384 KB Output is correct
14 Correct 1 ms 384 KB Output is correct
15 Correct 1 ms 384 KB Output is correct
16 Correct 0 ms 288 KB Output is correct

Subtask #7
27.0 / 27.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 384 KB Output is correct
2 Correct 1 ms 384 KB Output is correct
3 Correct 0 ms 384 KB Output is correct
4 Correct 1 ms 384 KB Output is correct
5 Correct 1 ms 384 KB Output is correct
6 Correct 0 ms 384 KB Output is correct
7 Correct 1 ms 384 KB Output is correct
8 Correct 1 ms 384 KB Output is correct
9 Correct 1 ms 384 KB Output is correct
10 Correct 1 ms 384 KB Output is correct
11 Correct 18 ms 1664 KB Output is correct
12 Correct 29 ms 2932 KB Output is correct
13 Correct 31 ms 2940 KB Output is correct
14 Correct 28 ms 2940 KB Output is correct
15 Correct 1 ms 384 KB Output is correct
16 Correct 5 ms 708 KB Output is correct
17 Correct 17 ms 1664 KB Output is correct
18 Correct 33 ms 2932 KB Output is correct
19 Correct 36 ms 2916 KB Output is correct
20 Correct 1 ms 384 KB Output is correct
21 Correct 4 ms 640 KB Output is correct
22 Correct 17 ms 1792 KB Output is correct
23 Correct 33 ms 2940 KB Output is correct
24 Correct 34 ms 2972 KB Output is correct
25 Correct 0 ms 384 KB Output is correct
26 Correct 1 ms 384 KB Output is correct
27 Correct 1 ms 384 KB Output is correct
28 Correct 1 ms 384 KB Output is correct
29 Correct 1 ms 384 KB Output is correct
30 Correct 4 ms 640 KB Output is correct
31 Correct 5 ms 640 KB Output is correct
32 Correct 20 ms 1664 KB Output is correct
33 Correct 22 ms 1664 KB Output is correct
34 Correct 43 ms 2940 KB Output is correct
35 Correct 40 ms 2932 KB Output is correct
36 Correct 44 ms 2932 KB Output is correct
37 Correct 44 ms 2932 KB Output is correct
38 Correct 0 ms 384 KB Output is correct
39 Correct 43 ms 2932 KB Output is correct
40 Correct 40 ms 2940 KB Output is correct
41 Correct 37 ms 2928 KB Output is correct
42 Correct 35 ms 2932 KB Output is correct