Submission #1281456

#	Time	Username	Problem	Language	Result	Execution time	Memory
1281456		TVSown	Flooding Wall (BOI24_wall)	C++20	8 / 100	96 ms	1248 KiB

Main

///*** Sown_Vipro ***///
/// ->TEAM SELECTION TEST<- ///

#include<bits/stdc++.h>
using namespace std;
//#pragma GCC optimize ("O3")
//#pragma GCC optimize ("unroll-loops")
//#pragma GCC target("popcnt")
#define F first
#define S second
#define pb push_back
#define pi pair<int, int>
#define pii pair<int, pair<int, int> >
#define FOR(i, a, b) for(int i = a; i <= b; ++i)
#define REP(i, a, b) for(int i = a; i >= b; --i)
#define all(s) s.begin(), s.end()
#define szz(s) int(s.size())
const string NAME = "sown";
const int N = 1e6 + 5, MAX = 1e6, MOD = 1e9 + 7;
void maxi(int &x, int y){ if(x < y) x = y; }
void mini(int &x, int y){ if(x > y) x = y; };
void add(int &x, int y){ x += y; x += MOD * (x < 0); x -= MOD * (x >= MOD); };
void fixmod(int &x){
    x += MOD * (x < 0); x -= MOD * (x >= MOD);
}
int n;
int a[N], b[N], c[N];

namespace sub1{
    int l[N], r[N];
    void solve(){
        int res = 0;
        FOR(mask, 0, (1 << n) - 1){

            FOR(i, 1, n){
                if(mask & (1 << i - 1)) c[i] = b[i];
                else c[i] = a[i];

                l[i] = max(l[i - 1], c[i]);
            }

            REP(i, n, 1){
                r[i] = max(r[i + 1], c[i]);

//                cout << l[i] << " " << r[i] << "\n";
                add(res, min(l[i], r[i]) - c[i]);
            }
//            break;
        }
        cout << res;
    }
}

namespace sub2{
    int res;
    int suf[2][1005][1005];

    void calc(int i, int x, int t){
        int pre = 1;
        FOR(j, 1, i - 1){
            pre = pre * ((a[j] <= x) + (b[j] <= x));
            fixmod(pre);
        }

        FOR(j, i + 1, n - 1){
            if(a[j] < x){
//                cout << i << " " << j << " " << pre << " " << suf[t][i][j + 1] << " " << (x - a[j]) << "\n";
                add(res, 1ll * pre * suf[t][i][j + 1] % MOD * (x - a[j]) % MOD);
            }

            if(b[j] < x){
//                cout << i << " " << j << " " << pre << " " << suf[t][i][j + 1] << " " << (x - b[j]) << "\n";
                add(res, 1ll * pre * suf[t][i][j + 1] % MOD * (x - b[j]) % MOD);
            }

            if(a[j] >= x && b[j] >= x) break;
        }
    }

    void rcalc(int i, int x, int t){
        int pre = 1;
        FOR(j, 1, i - 1){
            pre = pre * ((a[j] <= x) + (b[j] <= x));
            fixmod(pre);
        }

        FOR(j, i + 1, n - 1){
            if(a[j] < x){
//                cout << x << " " << j << " " << a[j] << " " << suf[t][i][j + 1] << "\n";
                add(res, 1ll * pre * suf[t][i][j + 1] % MOD * (x - a[j]) % MOD);
//                add(res, 1ll * pre * suf[t][i][j + 1] % MOD * (x - b[j]) % MOD);
            }

            if(b[j] < x){
                add(res, 1ll * pre * suf[t][i][j + 1] % MOD * (x - b[j]));
            }

            if(a[j] >= x && b[j] >= x) break;
        }
    }

    void solve(){
        FOR(i, 1, n){
            REP(j, n, i + 1){
                suf[0][i][j] = suf[0][i][j + 1];
                int ans = 1;
                FOR(k, i + 1, j - 1){
                    ans *= ((a[k] < a[i]) + (b[k] < a[i]));
                    fixmod(ans);
                }

                ans *= ((a[j] >= a[i]) + (b[j] >= a[i]));
                fixmod(ans);

                ans = 1ll * ans * (1 << (n - j)) % MOD;

                add(suf[0][i][j], ans);

                //
                suf[1][i][j] = suf[1][i][j + 1];
                ans = 1;
                FOR(k, i + 1, j - 1){
                    ans *= ((a[k] < b[i]) + (b[k] < b[i]));
                    fixmod(ans);
                }

                ans *= ((a[j] >= b[i]) + (b[j] >= b[i]));
                fixmod(ans);

                ans = 1ll * ans * (1 << (n - j)) % MOD;

//                cout << i << " " << j << " " << suf[1][i][j] << " " << ans << "\n";
                add(suf[1][i][j], ans);
            }
        }
//        cout << suf[1][1][3] << "\n";
        FOR(i, 1, n){
            calc(i, a[i], 0);
            calc(i, b[i], 1);
        }
        reverse(a + 1, a + 1 + n);
        reverse(b + 1, b + 1 + n);

        FOR(i, 1, n){
            REP(j, n, i + 1){
                suf[0][i][j] = suf[0][i][j + 1];
                int ans = 1;
                FOR(k, i + 1, j - 1){
                    ans *= ((a[k] < a[i]) + (b[k] < a[i]));
                    fixmod(ans);
                }

                ans *= ((a[j] > a[i]) + (b[j] > a[i]));
                fixmod(ans);

                ans = 1ll * ans * (1 << (n - j)) % MOD;

                add(suf[0][i][j], ans);
//                cout << i << " " << j << " " << suf[0][i][j] << "\n";

                //
                suf[1][i][j] = suf[1][i][j + 1];
                ans = 1;
                FOR(k, i + 1, j - 1){
                    ans *= ((a[k] < b[i]) + (b[k] < b[i]));
                    fixmod(ans);
                }

                ans *= ((a[j] > b[i]) + (b[j] > b[i]));
                fixmod(ans);

                ans = 1ll * ans * (1 << (n - j)) % MOD;

                add(suf[1][i][j], ans);
//                cout << ans << "\n";
//                break;
            }
//            break;
        }

//        cout << suf[1][1][3] << "\n";

        FOR(i, 1, n){
            rcalc(i, a[i], 0);
            rcalc(i, b[i], 1);
//            break;
        }

        cout << res;
    }
}

void solve(){
    cin >> n;
    FOR(i, 1, n) cin >> a[i];
    FOR(i, 1, n) cin >> b[i];

    // sub2::solve();
    if(n <= 20) sub1::solve();
    else sub2::solve();
}

signed main(){
    ios_base::sync_with_stdio(false);
    cin.tie(0); cout.tie(0);
    if(fopen((NAME + ".inp").c_str(), "r")){
        freopen((NAME + ".inp").c_str(), "r", stdin);
//        freopen((NAME + ".out").c_str(), "w", stdout);
    }
    int t = 1;
//    cin >> t;
    while(t--){
        solve();
    }
}

Compilation message (stderr)

Main.cpp: In function 'int main()':
Main.cpp:207:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  207 |         freopen((NAME + ".inp").c_str(), "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 8 / 8
• Subtask 2: 0 / 17
• Subtask 3: 0 / 19
• Subtask 4: 0 / 14
• Subtask 5: 0 / 12
• Subtask 6: 0 / 30