oj.uz

Submission #947977

# Submission time Handle Problem Language Result Execution time Memory
947977 2024-03-17T10:57:55 Z tnknguyen_ Fancy Fence (CEOI20_fancyfence) C++14
100 / 100
 27 ms 6236 KB 
#include <bits/stdc++.h>
using namespace std;
#define int long long
#define endl '\n' 

const int MOD = 1e9 + 7;
const int sz = 1e5 + 5;
long long INV;
long long h[sz], w[sz];
long long s[sz], f[sz];

long long bp(long long a, long long b){
    long long ans = 1;
    while(b){
        if(b & 1){
            ans = (ans * a) % MOD;
        }
        a = (a % MOD) * (a % MOD) % MOD;
        b >>= 1;
    }

    return ans;
}

long long c2(long long x){
    return (x * (x+1) % MOD) * (INV % MOD) % MOD;
}

long long add(long long a, long long b){
    return ((a % MOD) + (b % MOD)) % MOD;
}

long long mul(long long a, long long b){
    return (a % MOD) * (b % MOD) % MOD;
}

int32_t main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    //freopen("main.inp","r",stdin);
    //freopen("main.out","w",stdout);

    int n;
    cin>>n;

    for(int i=1;i<=n;++i){
        cin>>h[i];
    }
    for(int i=1;i<=n;++i){
        cin>>w[i];
        s[i] = (s[i-1] + w[i]) % MOD;
    }
    INV = bp(2, MOD-2);

    stack<int> st; //ascending stack
    st.push(0);
    long long ans = 0;
    for(int i=1;i<=n;++i){
        while(st.size() && h[st.top()] >= h[i]){ //h[st.top()] < h[i]
            st.pop();
        }

        long long len = (s[i] - s[st.top()] + MOD) % MOD;
        long long l1 = (len - w[i] + MOD) % MOD;

        long long A = 0; //equal heights.
        long long B = 0; //smaller heights.

        //# of sub-rect in current section.
        A += mul(c2(h[i]), c2(w[i])); 
        //# of sub-rect of section with height >= h[i] appended to current section.
        A += mul(mul(w[i], l1), c2(h[i])); 
        A %= MOD;

        B += mul(f[st.top()], w[i]);
        B %= MOD;

        f[i] = add(f[st.top()], mul(len, c2(h[i])));

        st.push(i);
        ans = (ans + A + B) % MOD;
    }
    cout<<ans;

    return 0;
}

Subtask #1
0.0 / 0.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2396 KB Output is correct
2 Correct 1 ms 2396 KB Output is correct

Subtask #2
12.0 / 12.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2396 KB Output is correct
2 Correct 1 ms 2396 KB Output is correct
3 Correct 1 ms 2512 KB Output is correct
4 Correct 1 ms 2396 KB Output is correct
5 Correct 0 ms 2396 KB Output is correct

Subtask #3
13.0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2396 KB Output is correct
2 Correct 1 ms 2396 KB Output is correct
3 Correct 8 ms 3536 KB Output is correct
4 Correct 15 ms 4700 KB Output is correct
5 Correct 16 ms 4564 KB Output is correct
6 Correct 16 ms 4692 KB Output is correct

Subtask #4
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2396 KB Output is correct
2 Correct 3 ms 2764 KB Output is correct
3 Correct 10 ms 3928 KB Output is correct
4 Correct 18 ms 5468 KB Output is correct
5 Correct 20 ms 5468 KB Output is correct
6 Correct 1 ms 2392 KB Output is correct

Subtask #5
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2648 KB Output is correct
2 Correct 1 ms 2396 KB Output is correct
3 Correct 2 ms 2652 KB Output is correct
4 Correct 9 ms 4068 KB Output is correct
5 Correct 19 ms 5468 KB Output is correct
6 Correct 20 ms 5564 KB Output is correct
7 Correct 1 ms 2396 KB Output is correct
8 Correct 2 ms 2908 KB Output is correct
9 Correct 9 ms 4188 KB Output is correct
10 Correct 18 ms 5972 KB Output is correct
11 Correct 18 ms 6236 KB Output is correct
12 Correct 1 ms 2396 KB Output is correct

Subtask #6
18.0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2396 KB Output is correct
2 Correct 1 ms 2396 KB Output is correct
3 Correct 0 ms 2396 KB Output is correct
4 Correct 1 ms 2396 KB Output is correct
5 Correct 0 ms 2396 KB Output is correct
6 Correct 1 ms 2396 KB Output is correct
7 Correct 1 ms 2396 KB Output is correct
8 Correct 1 ms 2396 KB Output is correct
9 Correct 1 ms 2396 KB Output is correct
10 Correct 1 ms 2396 KB Output is correct
11 Correct 1 ms 2396 KB Output is correct
12 Correct 1 ms 2396 KB Output is correct
13 Correct 1 ms 2396 KB Output is correct
14 Correct 1 ms 2396 KB Output is correct
15 Correct 1 ms 2396 KB Output is correct
16 Correct 1 ms 2396 KB Output is correct

Subtask #7
27.0 / 27.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2396 KB Output is correct
2 Correct 1 ms 2396 KB Output is correct
3 Correct 1 ms 2392 KB Output is correct
4 Correct 1 ms 2396 KB Output is correct
5 Correct 0 ms 2396 KB Output is correct
6 Correct 1 ms 2396 KB Output is correct
7 Correct 1 ms 2396 KB Output is correct
8 Correct 1 ms 2396 KB Output is correct
9 Correct 1 ms 2396 KB Output is correct
10 Correct 1 ms 2396 KB Output is correct
11 Correct 8 ms 3616 KB Output is correct
12 Correct 16 ms 4952 KB Output is correct
13 Correct 16 ms 4700 KB Output is correct
14 Correct 16 ms 4696 KB Output is correct
15 Correct 1 ms 2396 KB Output is correct
16 Correct 2 ms 2652 KB Output is correct
17 Correct 9 ms 3932 KB Output is correct
18 Correct 18 ms 5464 KB Output is correct
19 Correct 19 ms 5460 KB Output is correct
20 Correct 1 ms 2396 KB Output is correct
21 Correct 2 ms 2908 KB Output is correct
22 Correct 9 ms 4020 KB Output is correct
23 Correct 18 ms 6232 KB Output is correct
24 Correct 27 ms 6236 KB Output is correct
25 Correct 1 ms 2392 KB Output is correct
26 Correct 1 ms 2396 KB Output is correct
27 Correct 1 ms 2556 KB Output is correct
28 Correct 1 ms 2396 KB Output is correct
29 Correct 1 ms 2396 KB Output is correct
30 Correct 3 ms 2652 KB Output is correct
31 Correct 2 ms 2652 KB Output is correct
32 Correct 9 ms 3832 KB Output is correct
33 Correct 10 ms 3932 KB Output is correct
34 Correct 18 ms 5204 KB Output is correct
35 Correct 18 ms 5212 KB Output is correct
36 Correct 19 ms 5276 KB Output is correct
37 Correct 19 ms 5460 KB Output is correct
38 Correct 1 ms 2392 KB Output is correct
39 Correct 18 ms 5460 KB Output is correct
40 Correct 18 ms 5320 KB Output is correct
41 Correct 19 ms 5544 KB Output is correct
42 Correct 18 ms 5724 KB Output is correct