Submission #1274553

#	Time	Username	Problem	Language	Result	Execution time	Memory
1274553		icebear	Flooding Wall (BOI24_wall)	C++20	44 / 100	515 ms	1114112 KiB

Main

// ~~ icebear ~~
#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef pair<int, int> ii;
typedef pair<int, ii> iii;

template<class T>
    bool minimize(T &a, const T &b) {
        if (a > b) return a = b, true;
        return false;
    }

template<class T>
    bool maximize(T &a, const T &b) {
        if (a < b) return a = b, true;
        return false;
    }

#define FOR(i,a,b) for(int i=(a); i<=(b); ++i)
#define FORR(i,a,b) for(int i=(a); i>=(b); --i)
#define REP(i, n) for(int i=0; i<(n); ++i)
#define RED(i, n) for(int i=(n)-1; i>=0; --i)
#define MASK(i) (1LL << (i))
#define BIT(S, i) (((S) >> (i)) & 1)
#define mp make_pair
#define pb push_back
#define fi first
#define se second
#define all(x) x.begin(), x.end()
#define task "icebear"

const int MOD = 1e9 + 7;
const int inf = 1e9 + 27092008;
const ll INF = 1e18 + 27092008;
const int N = 5e5 + 5;
int n, a[N], b[N];
vector<int> compress, pL, pR;
vector<vector<int>> dpL, dpR;

void init(void) {
    cin >> n;
    FOR(i, 1, n) cin >> a[i], compress.pb(a[i]);
    FOR(i, 1, n) cin >> b[i], compress.pb(b[i]);
    sort(all(compress));
    compress.resize(unique(all(compress)) - compress.begin());
    FOR(i, 1, n) a[i] = lower_bound(all(compress), a[i]) - compress.begin() + 1;
    FOR(i, 1, n) b[i] = lower_bound(all(compress), b[i]) - compress.begin() + 1;
}

void process(void) {
    int MAX = (int)compress.size();
    dpL.resize(n + 5, vector<int>(MAX + 5, 0));
    dpR.resize(n + 5, vector<int>(MAX + 5, 0));
    pL.resize(max(n, MAX) + 5, 0);
    pR.resize(max(n, MAX) + 5, 0);

    dpL[0][0] = dpR[n + 1][0] = 1;
    FOR(i, 0, n - 1) FOR(j, 0, MAX) {
        (dpL[i + 1][max(a[i + 1], j)] += dpL[i][j]) %= MOD;
        (dpL[i + 1][max(b[i + 1], j)] += dpL[i][j]) %= MOD;
    }

    FORR(i, n + 1, 2) FOR(j, 0, MAX) {
        (dpR[i - 1][max(a[i - 1], j)] += dpR[i][j]) %= MOD;
        (dpR[i - 1][max(b[i - 1], j)] += dpR[i][j]) %= MOD;
    }

    int ans = 0;
    FOR(i, 2, n - 1) {
        FOR(j, 1, MAX) pL[j] = (pL[j - 1] + dpL[i - 1][j]) % MOD;
        FOR(j, 1, MAX) pR[j] = (pR[j - 1] + dpR[i + 1][j]) % MOD;
        FOR(j, 1, MAX) if (dpL[i - 1][j] > 0) {
            int v1 = max(0, compress[j - 1] - compress[a[i] - 1]);
            int v2 = max(0, compress[j - 1] - compress[b[i] - 1]);
            (ans += 1LL * (v1 + v2) * dpL[i - 1][j] % MOD * (pR[MAX] - pR[j - 1] + MOD) % MOD) %= MOD;
        }
        FOR(k, 1, MAX) if (dpR[i + 1][k] > 0) {
            int v1 = max(0, compress[k - 1] - compress[a[i] - 1]);
            int v2 = max(0, compress[k - 1] - compress[b[i] - 1]);
            (ans += 1LL * (v1 + v2) * dpR[i + 1][k] % MOD * (pL[MAX] - pL[k] + MOD) % MOD) %= MOD;
        }
    }

    cout << ans;
}

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    if (fopen(task".inp", "r")) {
        freopen(task".inp", "r", stdin);
        freopen(task".out", "w", stdout);
    }
    int tc = 1;
//    cin >> tc;
    while(tc--) {
        init();
        process();
    }
    return 0;
}

Compilation message (stderr)

Main.cpp: In function 'int main()':
Main.cpp:93:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   93 |         freopen(task".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:94:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   94 |         freopen(task".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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