Submission #379443

#	Time	Username	Problem	Language	Result	Execution time	Memory
379443		ACmachine	Fancy Fence (CEOI20_fancyfence)	C++17	100 / 100	119 ms	7532 KiB

fancyfence

#include <bits/stdc++.h>
using namespace std;
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;

template<typename T> using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
template<typename T, typename U> using ordered_map = tree<T, U, less<T>, rb_tree_tag, tree_order_statistics_node_update>;

typedef long long ll;
typedef long double ld;

typedef pair<int,int> pii;
typedef pair<ll,ll> pll;

typedef vector<int> vi;
typedef vector<ll> vll;

#define FOR(i,j,k,in) for(int i=(j); i < (k);i+=in)
#define FORD(i,j,k,in) for(int i=(j); i >=(k);i-=in)
#define REP(i,b) FOR(i,0,b,1)
#define REPD(i,b) FORD(i,b,0,1)
#define pb push_back
#define mp make_pair
#define ff first
#define ss second
#define all(x) begin(x), end(x)
#define MANY_TESTS int tcase; cin >> tcase; while(tcase--)

const double EPS = 1e-9;
const int MOD = 1e9+7;
const ll INFF = 1e18;
const int INF = 1e9;
const ld PI = acos((ld)-1);
const vi dy = {1, 0, -1, 0, -1, 1, 1, -1};
const vi dx = {0, 1, 0, -1, -1, 1, -1, 1};

void DBG(){cout << "]" << endl;}
template<typename T, typename ...U> void DBG(const T& head, const U... args){ cout << head << "; "; DBG(args...); }
#define dbg(...) cout << "Line(" << __LINE__ << ") -> [" << #__VA_ARGS__ << "]: [", DBG(__VA_ARGS__);
#define chk() cout << "Check at line(" << __LINE__ << ") hit." << endl;

template<class T, unsigned int U>
ostream& operator<<(ostream& out, const array<T, U> &v){out << "[";  REP(i, U) out << v[i] << ", ";  out << "]"; return out;}
template <class T, class U>
ostream& operator<<(ostream& out, const pair<T, U> &par) {out << "[" << par.first << ";" << par.second << "]"; return out;}
template <class T>
ostream& operator<<(ostream& out, const set<T> &cont) { out << "{"; for( const auto &x:cont) out << x << ", "; out << "}"; return out; }
template <class T, class U>
ostream& operator<<(ostream& out, const map<T, U> &cont) {out << "{"; for( const auto &x:cont) out << x << ", "; out << "}"; return out; }
template<class T>
ostream& operator<<(ostream& out, const vector<T> &v){ out << "[";  REP(i, v.size()) out << v[i] << ", ";  out << "]"; return out;}

template<class T>
istream& operator>>(istream& in, vector<T> &v){ for(auto &x : v) in >> x; return in; }

const int mod = (int)1e9+7;
struct Mint{
    int val;
    Mint(){ val = 0; }
    Mint(long long v){
        val = (-mod <= v && v < mod) ? v : v%mod;
        if(val < 0) val+= mod;
    }
    // operators
    Mint operator-(){return Mint(-val);}
    Mint& operator+=(const Mint& other){ val+=other.val; if(val >= mod) val-=mod; return *this;}
    Mint& operator-=(const Mint& other){ val-=other.val; if(val < 0) val+=mod; return *this;}
    Mint& operator*=(const Mint& other){ val=((long long)val*other.val)%mod; return *this;}
    friend Mint binpow(Mint a, long long p){
        Mint res(1);
        while(p > 0){
            if(p&1) res*=a; a*=a; p>>=1;
        }
        return res;
    }
    friend Mint inv(Mint a){ return binpow(a, mod-2); }
    Mint& operator/=(const Mint &other){ return (*this)*=inv(other);}

    friend Mint operator+(Mint a, const Mint& b){ return a+=b; }
    friend Mint operator-(Mint a, const Mint& b){ return a-=b; }
    friend Mint operator*(Mint a, const Mint& b){ return a*=b; }
    friend Mint operator/(Mint a, const Mint& b){ return a/=b; }

    bool operator==(const Mint &other){return val == other.val;}
    bool operator!=(const Mint &other){return val != other.val;}
    bool operator<(const Mint &other){return val < other.val;}
    // io
    friend ostream& operator<<(ostream &out, Mint &a){ return out << a.val; }
};

Mint get_rect(ll h, ll w, ll h_orig){
    // upper part
    Mint indiv = Mint(h) * Mint(w);
    Mint slice = Mint(h) * Mint(w) * Mint(h + w - 2);
    slice /= Mint(2);
    Mint other = Mint(h) * Mint(w) * (Mint(h) * Mint(w) - Mint(h + w - 1));
    other /= Mint(4);
    // lower part
    Mint topslice = Mint(w) * Mint(h) * Mint(h_orig - h);
    Mint top_other = Mint(w) * Mint(h) * Mint(w - 1) * Mint(h_orig - h);
    top_other /= Mint(2);
    Mint res = indiv + slice + other + topslice + top_other;
    return res;
}
struct dsu{
    vector<int> p;
    vector<ll> w;
    vector<ll> h;
    vector<int> la;
    vector<int> ra;
    vector<array<int, 2>> largest;
    int n;
    dsu(int _n, vector<int> _h, vector<int> _w) : n(_n){
        p.resize(n, -1);
        w.resize(n);
        REP(i, n)
            w[i] = _w[i];
        h.resize(n);
        REP(i, n)
            h[i] = _h[i];
        REP(i, n)
            largest.pb({_h[i], i});
        sort(all(largest));
        reverse(all(largest));
        la.resize(n);
        ra.resize(n);
        REP(i, n){
            la[i] = i - 1;
        }
        REP(i, n){
            ra[i] = i + 1;
        }
        ra[n - 1] = -1;
    }
    int find(int x){
        if(x == -1) return -1;
        return (p[x] < 0 ? x : (p[x] = find(p[x])));
    }
    void join(int a, int b){
        a = find(a);
        b = find(b);
        la[b] = la[a];
        h[b] = min(h[a], h[b]);
        w[b] = w[a] + w[b];
        p[a] = b;
    }
    Mint go(int num){
        array<int, 2> tp = largest[num];
        int id = tp[1]; id = find(id);
        int left = la[id]; int right = ra[id];
        left = find(left); right = find(right);
        if(left == -1 && right == -1){
            return get_rect(h[id], w[id], h[id]);
        }
        else if(left == -1){
            Mint ans =  get_rect(h[id] - h[right], w[id], h[id]);
            join(id, right);
            return ans;
        }
        else if(right == -1){
            Mint ans = get_rect(h[id] - h[left], w[id], h[id]);
            join(left, id);
            return ans;
        }
        else{
            if(h[left] >= h[right]){
                Mint ans = get_rect(h[id] - h[left], w[id], h[id]);
                join(left, id);
                return ans;
            }
            else{
                Mint ans = get_rect(h[id] - h[right], w[id], h[id]);
                join(id, right);
                return ans;
            }
        }
    }
};
int main(){
 	ios_base::sync_with_stdio(false);
 	cin.tie(NULL); cout.tie(NULL);
    int n; cin >> n;
    vector<int> h(n);
    cin >> h;
    vector<int> w(n);
    cin >> w;
    Mint ans(0);
    dsu d(n, h, w);
    REP(i, n){
        ans = ans + d.go(i);
    }
    cout << ans.val << "\n";
    return 0;
}

Compilation message (stderr)

fancyfence.cpp: In function 'Mint binpow(Mint, long long int)':
fancyfence.cpp:73:13: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
   73 |             if(p&1) res*=a; a*=a; p>>=1;
      |             ^~
fancyfence.cpp:73:29: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
   73 |             if(p&1) res*=a; a*=a; p>>=1;
      |                             ^

• Subtask 1: 0 / 0
• Subtask 2: 12 / 12
• Subtask 3: 13 / 13
• Subtask 4: 15 / 15
• Subtask 5: 15 / 15
• Subtask 6: 18 / 18
• Subtask 7: 27 / 27