Submission #461295

#	Time	Username	Problem	Language	Result	Execution time	Memory
461295		idas	Fountain (eJOI20_fountain)	C++11	30 / 100	287 ms	22588 KiB

fountain

#include <bits/stdc++.h>
#define FOR(i, begin, end) for(int i = (begin); i < (end); i++)
#define FAST_IO ios_base::sync_with_stdio(0); cin.tie(nullptr); cout.tie(nullptr)
#define F first
#define S second
#define PB push_back
#define MP make_pair
#define SZ(x) ((int)((x).size()))
#define LE(vec) vec[vec.size()-1]
#define TSTS int t; cin >> t; while(t--)solve()

const int INF = 1e9;
const long long LINF = 1e18;
const long double PI = asin(1)*2;
const int MOD = 1e9+7;

using namespace std;
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef map<int, int> mii;
typedef long long ll;
typedef long double ld;

void setIO()
{
    FAST_IO;
}

void setIO (string s) {
    setIO();
 	freopen((s+".in").c_str(),"r",stdin);
 	freopen((s+".out").c_str(),"w",stdout);
}

const int N=1e5+10, L=17;

int n, q, a[N], d[N], par[N][L], sm[N][L];
bool v[N];

void pre(int i)
{
    v[i]=true;
    int lst=i, dl=d[i];
    FOR(j, i+1, n)
    {
        if(d[j]>dl){
            v[j]=true;
            par[lst][0]=j;
            sm[lst][0]=a[j];
            lst=j;
            dl=d[j];
        }
    }
}

void build()
{
    FOR(i, 1, L)
    {
        FOR(j, 0, n+1)
        {
            par[j][i]=par[par[j][i-1]][i-1];
            sm[j][i]=sm[j][i-1]+sm[par[j][i-1]][i-1];
        }
    }
}

int main()
{
    setIO();
    cin >> n >> q;
    vector<pii> srt;
    FOR(i, 0, n)
    {
        cin >> d[i] >> a[i];
        srt.PB({d[i], i});
    }

    FOR(i, 0, n+1) par[i][0]=n;

    sort(srt.begin(), srt.end(), greater<pii>());
    set<int> used;
    used.insert(n);
    for(auto[x, i] : srt){
        auto nxt=used.upper_bound(i);
        par[i][0]=*nxt;
        if(*nxt!=n)
            sm[i][0]+=a[*nxt];
        used.insert(i);
    }

    build();
    FOR(i, 0, n+1)
    {
        FOR(j, 0, L)
        {
            if(par[i][j]==n){
                sm[i][j]=INF;
            }
        }
    }

    FOR(i, 0, q)
    {
        int p, x;
        cin >> p >> x;
        p--;
        int tot=a[p];
        if(tot>=x){
            cout << p+1 << '\n';
            continue;
        }
        bool going=true;
        while(going){
            going=false;
            for(int j=L-1; j>=0; j--){
                if(sm[p][j]+tot<x){
                    tot+=sm[p][j];
                    p=par[p][j];
                    going=true;
                }
            }
        }

        p=par[p][0];

        cout << (p==n?0:p+1) << '\n';
    }
}

Compilation message (stderr)

fountain.cpp: In function 'int main()':
fountain.cpp:84:13: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   84 |     for(auto[x, i] : srt){
      |             ^
fountain.cpp: In function 'void setIO(std::string)':
fountain.cpp:31:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   31 |   freopen((s+".in").c_str(),"r",stdin);
      |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
fountain.cpp:32:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   32 |   freopen((s+".out").c_str(),"w",stdout);
      |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 30
• Subtask 2: 30 / 30
• Subtask 3: 0 / 40