Submission #1270246

#	Time	Username	Problem	Language	Result	Execution time	Memory
1270246		ilovewaguri	Pilot (NOI19_pilot)	C++20	100 / 100	360 ms	47672 KiB

pilot

#include<bits/stdc++.h>
using namespace std;
#define NAME "CONCERT"
#define nl '\n'
#define allofa(x,sz) x,x+sz+1
#define allof(x) x.begin(),x.end()
#define allof1(x) x.begin()+1,x.end()
#define mset(x,val) memset(x,val,sizeof(x))
template<class T> T Abs(T &x) {return (x>=0 ? x : -x);};
template<class X,class Y> bool minimize(X &a, Y b){if(a>b) {a=b;return true;}return false;};
template<class X,class Y> bool maximize(X &a, Y b){if(a<b) {a=b;return true;}return false;};
typedef long long ll;
const ll mod = (long long)1e9+7;
const ll LINF = (long long)1e15;
const int INF = (int)1e9;
const int MAXN = (int)1e6+5;
vector<int> sorted;
ll res[MAXN];
int a[MAXN];
int n,q;

void ccps() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);cout.tie(0);
    if(fopen(NAME".inp","r")) {
        freopen(NAME".inp","r",stdin);
        freopen(NAME".out","w",stdout);
    }
}

namespace BruteForce {
    const int N = (int)1e5+5;
    ll fact[N],inv[N];

    bool check() {
        return n<=1e3 and q<=1e3;
    }

    ll indianPow(ll a, ll b) {
        if(b==0) return 1;
        if(b==1) return a;
        ll tmp = indianPow(a,b/2);
        if(b%2==0) return (tmp%mod * tmp%mod)%mod;
        return (tmp%mod * (tmp%mod * a%mod)%mod)%mod;
    }

    void init() {
        fact[0]=fact[1]=inv[0]=inv[1]=1;
        for (int i = 1; i<N; i++) {
            fact[i]=(fact[i-1]*i)%mod;
        }
        inv[N-1]=indianPow(fact[N-1],mod-2);
        for (int i = N-2; i>=1; i--) {
            inv[i] = (inv[i+1]*(i+1))%mod;
        }
    }

    ll nCk(int n, int k) {
        return ((fact[n]%mod * inv[k]%mod) * inv[n-k]%mod)%mod;
    }

    void sol() {
        init();
        while(q--) {
            int upper; cin >> upper;
            ll res = 0;
            int cnt = 0;
            for (int i = 1; i<=n; i++) {
                if(a[i]<=upper) {
                    cnt++;
                    res++;
                }
                else {
                    res+=nCk(cnt,2);
                    cnt=0;
                }
            }
            res+=nCk(cnt,2);
            cout << res << nl;
        }
    }
}

namespace FinalSol {
    ll nCk(int n) {
        return 1LL*n*(n+1)/2;
    }

    struct DSU {
        int par[MAXN],power[MAXN];

        void makeSet(int n) {
            for (int i = 1; i<=n; i++) {
                par[i]=i;
                power[i]=1;
            }
        }

        int find(int u) {
            return (u==par[u] ? u : par[u]=find(par[u]));
        }

        ll getVal(int u) {
            u=find(u);
            return nCk(power[u]);
        }

        bool Union(int u, int v, ll &res) {
            u=find(u);v=find(v);
            if(u==v) return false;
            if(power[u]<power[v]) swap(u,v);
            res-=getVal(u);
            res-=getVal(v);
            par[v]=u;
            power[u]+=power[v];
            res+=getVal(u);
            return true;
        }
    } dsu;

    struct query {
        int height, ID;
        bool operator <(const query &ot) const {
            return height<ot.height;
        }
    };

    struct info {
        int val,ID;
        bool operator <(const info &ot) const {
            return val<ot.val;
        }
    };

    void sol() {
        vector<query> queries;
        vector<info> sorted;
        bool canReach[n+5];
        mset(canReach,false);
        for (int i = 1; i<=n; i++) {
            sorted.push_back({a[i],i});
        }
        for (int i = 1; i<=q; i++) {
            int height; cin >> height;
            queries.push_back({height,i});
        }
        int ptr = 0;
        ll curRes = 0;
        sort(allof(sorted));
        sort(allof(queries));
        dsu.makeSet(n);
        for (query x : queries) {
            int h = x.height;
            int id = x.ID;
            while(ptr<n and sorted[ptr].val<=h) {
                int pos = sorted[ptr].ID;
                canReach[pos]=true;
                curRes++;
                if(pos>1 and canReach[pos-1]) dsu.Union(pos,pos-1,curRes);
                if(pos<n and canReach[pos+1]) dsu.Union(pos,pos+1,curRes);
                ptr++;
            }
            res[id] = curRes;
        }
        for (int i = 1; i<=q; i++) {
            cout << res[i] << nl;
        }
    }
}

signed main() {
    ccps();
    cin >> n >> q;
    for (int i = 1; i<=n; i++) {
        cin >> a[i];
        sorted.push_back(a[i]);
    }
    if(BruteForce::check()) BruteForce::sol();
    else FinalSol::sol();
}

Compilation message (stderr)

pilot.cpp: In function 'void ccps()':
pilot.cpp:26:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   26 |         freopen(NAME".inp","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
pilot.cpp:27:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   27 |         freopen(NAME".out","w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 3 / 3
• Subtask 2: 10 / 10
• Subtask 3: 12 / 12
• Subtask 4: 15 / 15
• Subtask 5: 5 / 5
• Subtask 6: 9 / 9
• Subtask 7: 14 / 14
• Subtask 8: 10 / 10
• Subtask 9: 11 / 11
• Subtask 10: 11 / 11