Submission #642475

#	Time	Username	Problem	Language	Result	Execution time	Memory
642475		Carmel_Ab1	Fountain (eJOI20_fountain)	C++17	100 / 100	431 ms	41796 KiB

fountain

/*
#pragma GCC target ("avx2")
#pragma GCC optimization ("O3")
#pragma GCC optimization ("unroll-loops")
 */
#include<bits/stdc++.h>
//#include <ext/pb_ds/assoc_container.hpp>
//#include <ext/pb_ds/tree_policy.hpp>

//using namespace __gnu_pbds;
using namespace std;

typedef long double ld;
typedef long long ll;
typedef unsigned long long ull;
typedef vector<int>vi;
typedef vector<vector<int>>vvi;
typedef vector<ll>vl;
typedef vector<vl> vvl;
typedef pair<int,int>pi;
typedef pair<ll,ll> pl;
typedef vector<pl> vpl;
typedef vector<ld> vld;
typedef pair<ld,ld> pld;
typedef vector<pi> vpi;

//typedef tree<ll, null_type, less_equal<ll>,rb_tree_tag,tree_order_statistics_node_update> ordered_set;
template<typename T> ostream& operator<<(ostream& os, vector<T>& a){os<<"[";for(int i=0; i<ll(a.size()); i++){os << a[i] << ((i!=ll(a.size()-1)?" ":""));}os << "]\n"; return os;}

#define all(x) x.begin(),x.end()
#define YES out("YES")
#define NO out("NO")
#define out(x){cout << x << "\n"; return;}
#define outfl(x){cout << x << endl;return;}
#define GLHF ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL)
#define print(x){for(auto ait:x) cout << ait << " "; cout << "\n";}
#define pb push_back
#define umap unordered_map

template<typename T1, typename T2> istream& operator>>(istream& is, pair<T1, T2>& p){is >> p.first >> p.second;return is;}
template<typename T1, typename T2> ostream& operator<<(ostream& os, pair<T1, T2>& p){os <<"" << p.first << " " << p.second << ""; return os;}
void usaco(string taskname){
    string fin = taskname + ".in";
    string fout = taskname + ".out";
    const char* FIN = fin.c_str();
    const char* FOUT = fout.c_str();
    freopen(FIN, "r", stdin);
    freopen(FOUT, "w", stdout);
}
template<typename T>
void read(vector<T>& v){
    int n=v.size();
    for(int i=0; i<n; i++)
        cin >> v[i];
}
template<typename T>
vector<T>UNQ(vector<T>a){
    vector<T>ans;
    for(T t:a)
        if(ans.empty() || t!=ans.back())
            ans.push_back(t);
    return ans;
}



void solve();
int main(){
    GLHF;
    int t=1;
    //cin >> t;
    while(t--)
        solve();
}
vi nxt_greater(vi a){
    int n=a.size();
    vi nxt(n,-1);
    stack<int>S;

    for(int i=0; i<n; i++){
        while(S.size() && a[S.top()]<a[i]){
            nxt[S.top()]=i;
            S.pop();
        }
        S.push(i);
    }
    return nxt;
}

void solve() {
    int n,q;
    cin >> n >> q;
    vi D(n+1),C(n+1);
    for(int i=1; i<=n; i++)
        cin >> D[i] >> C[i];

    vi nxt_g= nxt_greater(D);
    int lg=18;

    vvl dp(n+1,vl(lg,1e18)),nxt(n+1,vl(lg,-1));//sum of first 2^j on path starts from i
    for(int i=1; i<=n; i++)
        nxt[i][0]=nxt_g[i],dp[i][0]=C[i];

    for(int j=1; j<lg; j++) {
        for (int i = 1; i <= n; i++)
            if (nxt[i][j - 1] != -1) {
                nxt[i][j] = nxt[nxt[i][j - 1]][j - 1];
                dp[i][j]=dp[i][j-1]+dp[nxt[i][j-1]][j-1];
            }
    }

    while(q--){
        int r,v;
        cin >> r >> v;
        int ans=r;
        for(int i=lg-1; i>=0; i--)
            if(dp[ans][i]<v)
                v-=dp[ans][i],ans=nxt[ans][i];

        if(!(ans!=-1 && C[ans]>=v))
            ans=0;
        cout << ans << "\n";
    }
}

Compilation message (stderr)

fountain.cpp: In function 'void usaco(std::string)':
fountain.cpp:47:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   47 |     freopen(FIN, "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~
fountain.cpp:48:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   48 |     freopen(FOUT, "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~

• Subtask 1: 30 / 30
• Subtask 2: 30 / 30
• Subtask 3: 40 / 40