Submission #1062074

#TimeUsernameProblemLanguageResultExecution timeMemory
1062074Jarif_RahmanFlooding Wall (BOI24_wall)C++17
0 / 100
4 ms4188 KiB
#include <bits/stdc++.h>
#define pb push_back
#define f first
#define sc second
using namespace std;
typedef long long int ll;
typedef string str;

const ll md = 1e9+7;
const int N = 5e5+5;
ll pw2[N];

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

    pw2[0] = 1;
    for(int i = 1; i < N; i++) pw2[i] = (pw2[i-1]*2)%md;

    int n; cin >> n;
    vector<int> A(n), B(n);
    int m = 0;
    for(int &x: A) cin >> x, m = max(m, x);
    for(int &x: B) cin >> x, m = max(m, x);
    for(int i = 0; i < n; i++) if(A[i] > B[i]) swap(A[i], B[i]);

    m++;
    vector<int> cmn(m, 0), cmx(m, 0);
    for(int i = 0; i < n; i++) cmn[A[i]]++, cmx[B[i]]++;

    ll ans = 0;
    for(int i = 0; i+1 < n; i++){
        cmn[A[i]]--, cmx[B[i]]--;
        int x = 0, y = 0;
        for(int j = m-1; j > B[i]; j--) x+=cmn[j], y+=cmx[j];
        for(int j = B[i]; j > A[i]; j--){
            x+=cmn[j], y+=cmx[j];
            if(x > 0) ans+=pw2[n-1], ans%=md;
            else if(y > 0) ans+=(pw2[n-1-y]*(pw2[y]-1))%md, ans%=md;
        }
        for(int j = A[i]; j >= 1; j--){
            x+=cmn[j], y+=cmx[j];
            if(x > 0) ans+=pw2[n], ans%=md;
            else if(y > 0) ans+=(pw2[n-y]*(pw2[y]-1))%md, ans%=md;
        }
    }
    /*ans+=((A[0]+B[0])*pw2[n-1])%md;
    for(int i = 1; i < n; i++){
        if(A[i] > A[i-1]) ans+=((A[i]-A[i-1])*pw2[n-2])%md, ans%=md;
        if(B[i] > A[i-1]) ans+=((B[i]-A[i-1])*pw2[n-2])%md, ans%=md;
        if(A[i] > B[i-1]) ans+=((A[i]-B[i-1])*pw2[n-2])%md, ans%=md;
        if(B[i] > B[i-1]) ans+=((B[i]-B[i-1])*pw2[n-2])%md, ans%=md;
    }*/

    /*for(int i = 0; i < n; i++) ans-=((A[i]+B[i])*pw2[n-1])%md, ans%=md;
    if(ans < 0) ans+=md;*/
    cout << ans << "\n";
}
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