Submission #1197649

#	Time	Username	Problem	Language	Result	Execution time	Memory
1197649		InvMOD	마스코트 (JOI13_mascots)	C++17	100 / 100	1356 ms	99276 KiB

mascots

#include<bits/stdc++.h>

using namespace std;

#define fi first
#define se second
#define pb push_back
#define eb emplace_back

#define vi vector<int>
#define pi pair<int,int>
#define sz(v) (int)(v).size()
#define all(v) (v).begin(), (v).end()
#define compact(v) (v).erase(unique(all(v)), (v).end())

template<class T> using upq = priority_queue<T, vector<T>, greater<T>>;
template<class T> int lwrbound(const vector<T>& a, const T& b, const int s = 0){return int(lower_bound(s + all(a), b) - a.begin());}
template<class T> int uprbound(const vector<T>& a, const T& b, const int s = 0){return int(upper_bound(s + all(a), b) - a.begin());}

#define FOR(i, a, b) for(int i = (a); i <= (b); i++)
#define ROF(i, a, b) for(int i = (a); i >= (b); i--)
#define sumof(x) accumulate(all(x), 0ll)
#define dbg(x) "[" << #x " = " << (x) << "]"
#define el "\n"

using ll = long long;
using ld = long double;

template<class T> bool ckmx(T& a, const T b){return (a < b ? a = b, true : false);}
template<class T> bool ckmn(T& a, const T b){return (a > b ? a = b, true : false);}

const int N = 2e5 + 5;
const int MOD = 1e9 + 7;
const ll INF = numeric_limits<ll>::max() / 8;

int add(int x, int y){
    return (x + y < MOD ? x + y : x + y - MOD);
}

int mul(int x, int y){
    return (1ll * x * y) % MOD;
}

int bpow(int a, int b){
    int ans = 1; assert(b >= 0);
    for(; b; b >>= 1, a = mul(a, a)){
        if(b & 1) ans = mul(ans, a);
    }
    return ans;
}

void Main()
{
    int n,m; cin >> n >> m;

    int k; cin >> k;

    int x1 = n, x2 = 0, y1 = m, y2 = 0;
    FOR(i, 1, k){
        int a,b; cin >> a >> b;

        ckmn(x1, a), ckmx(x2, a);
        ckmn(y1, b), ckmx(y2, b);
    }

    vi fact(n * m + 1, 0), invf(n * m + 1, 0);
    fact[0] = 1, invf[0] = 1;
    FOR(i, 1, n * m){
        fact[i] = mul(fact[i - 1], i);
        invf[i] = bpow(fact[i], MOD - 2);
    }

    auto C = [&](int n, int k) -> int{
        return mul(fact[n], mul(invf[n - k], invf[k]));
    };

    int got_x = x2 - x1 + 1, got_y = y2 - y1 + 1;
    int needx = n - got_x, needy = m - got_y;

    // How to build a full rectangle that get max happiness
    vector<vi> dp(needx + 1, vi(needy + 1, 0));

    dp[0][0] = 1;
    FOR(i, 0, needx){
        FOR(j, 0, needy){
            if(!i && !j) continue;

            if(i) dp[i][j] = add(dp[i][j], mul(dp[i - 1][j], fact[j + got_y]));
            if(j) dp[i][j] = add(dp[i][j], mul(dp[i][j - 1], fact[i + got_x]));
        }
    }

    int ans = dp[needx][needy];

    // we need to care the order of choosing row, column
    ans = mul(ans, mul(C(needx, x1 - 1), C(needy, y1 - 1)));

    // how to build a rectangle [x1, y1, x2, y2] ?
    ans = mul(ans, fact[got_x * got_y - k]);

    cout << ans << el;
}

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

    #define name "InvMOD"
    if(fopen(name".INP", "r")){
        freopen(name".INP", "r", stdin);
        freopen(name".OUT", "w", stdout);
    }

    int t = 1; while(t--) Main();
    return 0;
}

Compilation message (stderr)

mascots.cpp: In function 'int32_t main()':
mascots.cpp:111:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  111 |         freopen(name".INP", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
mascots.cpp:112:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  112 |         freopen(name".OUT", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 30 / 30
• Subtask 3: 60 / 60