Submission #1129229

#	Time	Username	Problem	Language	Result	Execution time	Memory
1129229		Mher777	Flooding Wall (BOI24_wall)	C++20	17 / 100	4 ms	3404 KiB

Main

#define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <iomanip>
#include <array>
#include <string>
#include <algorithm>
#include <cmath>
#include <set>
#include <map>
#include <unordered_set>
#include <unordered_map>
#include <vector>
#include <stack>
#include <queue>
#include <deque>
#include <bitset>
#include <list>
#include <iterator>
#include <numeric>
#include <complex>
#include <utility>
#include <random>
#include <cassert>
#include <fstream>
using namespace std;
mt19937 rnd(time(nullptr));

/* -------------------- Typedefs -------------------- */

typedef int itn;
typedef long long ll;
typedef unsigned long long ull;
typedef double db;
typedef float fl;
typedef long double ld;

/* -------------------- Usings -------------------- */

using vi = vector<int>;
using vll = vector<ll>;
using mii = map<int, int>;
using mll = map<ll, ll>;
using pii = pair<int, int>;
using pll = pair<ll, ll>;

/* -------------------- Defines -------------------- */

#define ff first
#define ss second
#define pub push_back
#define pob pop_back
#define puf push_front
#define pof pop_front
#define mpr make_pair
#define yes cout<<"Yes\n"
#define no cout<<"No\n"
#define all(x) (x).begin(), (x).end()
#define USACO freopen("feast.in", "r", stdin); freopen("feast.out", "w", stdout);

/* -------------------- Constants -------------------- */

const int dx[8] = { -1, 0, 1, 0, -1, -1, 1, 1 };
const int dy[8] = { 0, -1, 0, 1, -1, 1, -1, 1 };
const int MAX = int(1e9 + 5);
const ll MAXL = ll(1e18) + 5ll;
const ll MOD = ll(1000000007);
const ll MOD2 = ll(998244353);

/* -------------------- Functions -------------------- */

void fastio() {
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
}

void precision(int x) {
    cout.setf(ios::fixed | ios::showpoint);
    cout.precision(x);
}

ll gcd(ll a, ll b) {
    if (a == 0 || b == 0) return(max(a, b));
    while (b) {
        a %= b;
        swap(a, b);
    }
    return a;
}

ll lcm(ll a, ll b) {
    return a / gcd(a, b) * b;
}

ll range_sum(ll a, ll b) {
    if (a > b) return 0ll;
    ll dif = a - 1, cnt = b - a + 1;
    ll ans = ((b - a + 1) * (b - a + 2)) / 2;
    ans += ((b - a + 1) * dif);
    return ans;
}

string dec_to_bin(ll a) {
    string s = "";
    for (ll i = a; i > 0; ) {
        ll k = i % 2;
        i /= 2;
        char c = k + 48;
        s += c;
    }
    if (a == 0) {
        s = "0";
    }
    reverse(all(s));
    return s;
}

ll bin_to_dec(string s) {
    ll num = 0;
    for (int i = 0; i < s.size(); i++) {
        num *= 2ll;
        num += (s[i] - '0');
    }
    return num;
}

ll factorial_by_mod(ll n, ll mod) {
    ll ans = 1;
    ll num;
    for (ll i = 1; i <= n; ++i) {
        num = i % mod;
        ans *= num;
        ans %= mod;
    }
    return ans;
}

bool isPrime(ll a) {
    if (a == 1) return false;
    for (ll i = 2; i * i <= a; i++) {
        if (a % i == 0) return false;
    }
    return true;
}

ll binpow(ll a, ll b) {
    if (!a) return 0;
    ll ans = 1;
    while (b) {
        if (b & 1) {
            ans *= a;
        }
        b >>= 1;
        a *= a;
    }
    return ans;
}

ll binpow_by_mod(ll a, ll b, ll mod) {
    if (!a) return 0;
    ll ans = 1;
    while (b) {
        if (b & 1) {
            ans *= a;
            ans %= mod;
        }
        b >>= 1;
        a *= a;
        a %= mod;
    }
    return ans;
}

/* -------------------- Solution -------------------- */

const int N = 105, M = 1005;
ll dp[N][M], dp1[N][M], pref[N][M], pref1[N][M], a[N][2];

void slv() {
    int n;
    cin >> n;
    ll mx = 0;
    for (int i = 1; i <= n; ++i) {
        cin >> a[i][0];
    }
    for (int i = 1; i <= n; ++i) {
        cin >> a[i][1];
        if (a[i][1] < a[i][0]) {
            swap(a[i][1], a[i][0]);
        }
        mx = max(mx, a[i][1]);
    }
    dp[1][a[1][0]] = dp[1][a[1][1]] = 1ll;
    for (int i = 2; i <= n; ++i) {
        ll cnt = 0;
        for (int j = 1; j <= mx; ++j) {
            if (j < a[i][0]) {
                cnt += dp[i - 1][j];
                if (cnt >= MOD) {
                    cnt -= MOD;
                }
            }
            else if (j < a[i][1]) {
                cnt += dp[i - 1][j];
                if (cnt >= MOD) {
                    cnt -= MOD;
                }
                dp[i][j] = dp[i - 1][j];
            }
            else if (j == a[i][1]) {
                dp[i][j] = cnt + dp[i - 1][j] * 2ll;
                dp[i][j] %= MOD;
            }
            else {
                dp[i][j] = dp[i - 1][j] * 2ll;
                dp[i][j] %= MOD;
            }
            if (j == a[i][0]) {
                dp[i][j] = cnt;
            }
        }
    }
    dp1[n][a[n][0]] = dp1[n][a[n][1]] = 1ll;
    for (int i = n - 1; i >= 1; --i) {
        ll cnt = 0;
        for (int j = 1; j <= mx; ++j) {
            if (j < a[i][0]) {
                cnt += dp1[i + 1][j];
                if (cnt >= MOD) {
                    cnt -= MOD;
                }
            }
            else if (j < a[i][1]) {
                cnt += dp1[i + 1][j];
                if (cnt >= MOD) {
                    cnt -= MOD;
                }
                dp1[i][j] = dp1[i + 1][j];
            }
            else if (j == a[i][1]) {
                dp1[i][j] = cnt + dp1[i + 1][j] * 2ll;
                dp1[i][j] %= MOD;
            }
            else {
                dp1[i][j] = dp1[i + 1][j] * 2ll;
                dp1[i][j] %= MOD;
            }
            if (j == a[i][0]) {
                dp1[i][j] = cnt;
            }
        }
    }
    for (int i = 1; i <= n; ++i) {
        for (int j = mx; j >= 1; --j) {
            pref[i][j] = pref[i][j + 1] + dp[i][j];
            if (pref[i][j] >= MOD) {
                pref[i][j] -= MOD;
            }
            pref1[i][j] = pref1[i][j + 1] + dp1[i][j];
            if (pref1[i][j] >= MOD) {
                pref1[i][j] -= MOD;
            }
        }
    }
    ll ans = 0, cnt;
    for (int i = 1; i <= n; ++i) {
        for (int j = a[i][0] + 1; j <= mx; ++j) {
            cnt = dp[i - 1][j] * pref1[i + 1][j + 1];
            cnt %= MOD;
            cnt += pref[i - 1][j] * dp1[i + 1][j];
            cnt %= MOD;
            ans += cnt * (ll)(j - a[i][0]);
            ans %= MOD;
            if (j > a[i][1]) {
                ans += cnt * (ll)(j - a[i][1]);
                ans %= MOD;
            }
        }
    }
    cout << ans;
}

void cs() {
    int tstc = 1;
    //cin >> tstc;
    while (tstc--) {
        slv();
    }
}

void precalc() {
    return;
}

int main() {
    fastio();
    precalc();
    //precision(0);
    cs();
    return 0;
}

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