Submission #1010594

#	Time	Username	Problem	Language	Result	Execution time	Memory
1010594		yeediot	Flooding Wall (BOI24_wall)	C++17	70 / 100	5005 ms	45676 KiB

Main

#include<bits/stdc++.h>
using namespace std;
#define int long long
#define F first
#define S second
#define all(x) x.begin(),x.end()
#define pii pair<int,int>
#define pb push_back
#define sz(x) (int)(x.size())
#define chmin(x,y) x=min(x,y)
#define chmax(x,y) x=max(x,y)
#define vi vector<int>
#define vp vector<pii>
#define vvi vector<vi>
#define ykh mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count())
#define __lg(x) 63-__builtin_clzll(x)
#define pow2(x) (1LL<<x)
void __print(int x) {cerr << x;}
void __print(float x) {cerr << x;}
void __print(double x) {cerr << x;}
void __print(long double x) {cerr << x;}
void __print(char x) {cerr << '\'' << x << '\'';}
void __print(const char *x) {cerr << '\"' << x << '\"';}
void __print(const string &x) {cerr << '\"' << x << '\"';}
void __print(bool x) {cerr << (x ? "true" : "false");}

template<typename T, typename V>
void __print(const pair<T, V> &x) {cerr << '{'; __print(x.first); cerr << ','; __print(x.second); cerr << '}';}
template<typename T>
void __print(const T &x) {int f = 0; cerr << '{'; for (auto &i: x) cerr << (f++ ? "," : ""), __print(i); cerr << "}";}
void _print() {cerr << "]\n";}
template <typename T, typename... V>
void _print(T t, V... v) {__print(t); if (sizeof...(v)) cerr << ", "; _print(v...);}
void setIO(string s) {
    freopen((s + ".in").c_str(), "r", stdin);
    freopen((s + ".out").c_str(), "w", stdout);
}
#ifdef local
void CHECK();
void setio(){
    freopen("/Users/iantsai/cpp/input.txt","r",stdin);
    freopen("/Users/iantsai/cpp/output.txt","w",stdout);
}
#define debug(x...) cerr << "[" << #x << "] = ["; _print(x)
#else
void setio(){}
#define debug(x...)
#endif
#define TOI_is_so_de ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);setio();
const int mxn = 5e5+5, mod = 1e9+7;
int n, l[mxn], r[mxn], f[mxn], inv[mxn], pre[mxn];
bool vis[mxn];
vector<pii>ord;
queue<int> to;
int fpow(int a, int b){
    int res = 1;
    while(b){
        if(b&1) res = res*a%mod;
        a=a*a%mod;
        b >>= 1;
    }
    return res;
}
/*struct BIT{
    int bit[mxn];
    void init(){
        for(int i=0;i<mxn;i++){
            bit[i] = 0;
        }
    }
    void modify(int p,int v){
        for(;p<mxn;p+=p&-p){
            bit[p] += v;
        }
    }
    int query(int p){
        int res = 0;
        for(;p;p-=p&-p){
            res += bit[p];
        }
        return res;
    }
}bt;*/
signed main(){
    TOI_is_so_de;
    cin >> n;
    f[0] = 1;
    inv[0] = 1;
    for(int i=1;i<=n;i++){
        f[i] = f[i-1] * 2 % mod;
        inv[i] = fpow(f[i], mod-2);
    }
    int val = f[n-1], ans = 0, mx = 2;
    vector<int>temp;
    for(int i=1;i<=n;i++){
        cin >> l[i];
        chmax(mx, l[i]);
        temp.pb(l[i]);
    }
    for(int i=1;i<=n;i++){
        cin >> r[i];
        chmax(mx, r[i]);
        temp.pb(r[i]);
    }
    sort(all(temp));
    temp.resize(unique(all(temp))-temp.begin());
    int last = 0;
    for(auto H : temp){
        ord.clear();
        for(int i=1;i<=n;i++){
            pre[i] = 0;
        }
        vector<int>pos;
        for(int i=1;i<=n;i++){
            if(l[i] >= H){
                pre[i]++;
            }
            else{
                ord.pb({1, i});
            }
            if(r[i] >= H){
                pre[i]++;
                if(l[i] >= H){
                    pos.pb(i);
                }
            }
            else{
                ord.pb({1, i});
            }
        }
        debug(H, pos, ord);
        for(int i=1;i<=n;i++){
            pre[i] += pre[i-1];
        }
        int prev = -1, ptr = 0;
        for(auto [h, id] : ord){
            while(ptr < sz(pos) and pos[ptr] < id){
                ptr++;
            }
            int temp = val;
            if(ptr == 0){
                int x = pre[id-1];
                int val2 = f[x];
                temp = temp * inv[x] % mod * (val2 - 1) % mod;
            }
            if(ptr==sz(pos)){
                int x = pre[n] - pre[id];
                int val2 = f[x];
                temp = temp * inv[x] % mod * (val2 - 1) % mod;
            }
            ans = (ans + (H - last) * temp % mod) % mod;
        }
        while(sz(to)){
            auto v = to.front();
            to.pop();
            vis[v] = 0;
        }
        last = H;
        debug(ans);
    }
    cout << ans << '\n';
    #ifdef local
    CHECK();
    #endif
}
/*
input:
 
*/
#ifdef local
void CHECK(){
    cerr << "\n[Time]: " << 1000.0 * clock() / CLOCKS_PER_SEC << " ms.\n";
     function<bool(string,string)> compareFiles = [](string p1, string p2)->bool {
         std::ifstream file1(p1);
         std::ifstream file2(p2);
         if (!file1.is_open() || !file2.is_open())return false;
         std::string line1, line2;
         while (getline(file1, line1) && getline(file2, line2)) {
             if (line1 != line2)return false;
         }
         int cnta=0,cntb=0;
         while(getline(file1,line1))cnta++;
         while(getline(file2,line2))cntb++;
         return cntb-cnta<=1;
     };
     bool check = compareFiles("output.txt","expected.txt");
     if (check) cerr<<"ACCEPTED\n";
     else cerr<<"WRONG ANSWER!\n";
}
#else
#endif



 

Compilation message (stderr)

Main.cpp: In function 'int main()':
Main.cpp:135:13: warning: unused variable 'prev' [-Wunused-variable]
  135 |         int prev = -1, ptr = 0;
      |             ^~~~
Main.cpp: In function 'void setIO(std::string)':
Main.cpp:35:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   35 |     freopen((s + ".in").c_str(), "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:36:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   36 |     freopen((s + ".out").c_str(), "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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