Submission #472105

#	Time	Username	Problem	Language	Result	Execution time	Memory
472105		Cross_Ratio	Roller Coaster Railroad (IOI16_railroad)	C++14	0 / 100	79 ms	9780 KiB

railroad

#include <bits/stdc++.h>
//#include "railroad.h"
using namespace std;
const int INF = 1e9;
struct SegTree {
    struct Node {
        int ma, sum;
        Node(int m1, int m2) : ma(m1), sum(m2) {}
        Node(int v) : ma(v), sum(v) {}
        Node() : ma(INF),sum(0) {}
    };
    vector<Node> seg;
    int MAX;
    SegTree(int N) {
        int i;
        for(i=1;i<2*N;i*=2) {}
        seg.resize(i);
        MAX = i;
    }
    Node f(Node x, Node y) {
        return Node(max(x.ma,y.ma),x.sum+y.sum);
    }
    void cons() {
        for(int i = MAX/2-1; i>0; i--) {
            seg[i] = f(seg[2*i],seg[2*i+1]);
        }
    }
    Node sum(int s, int e, int n, int ns, int ne) {
        if(e<=ns||ne<=s) return Node();
        if(s<=ns&&ne<=e) return seg[n];
        int mid = ns + ne >> 1;
        return f(sum(s,e,2*n,ns,mid),sum(s,e,2*n+1,mid,ne));
    }
    void update(int n) {
        n += MAX/2;
        n /= 2;
        while(n) {
            seg[n] = f(seg[2*n],seg[2*n+1]);
            n /= 2;
        }
    }
    void Plus(int n, int a) {
        int b = seg[n+MAX/2].ma;
        seg[n+MAX/2] = Node(b+a);
        update(n);
    }
    void Edit(int n, int a) {
        seg[n+MAX/2] = Node(a);
        update(n);
    }
    Node sum(int s, int e) {
        if(s >= e) return Node();
        return sum(s, e, 1, 0, MAX/2);
    }
    int FindLeft(int s, int e) {
        if(s + 1 == e) {
            if(seg[s+MAX/2].ma==1) return s;
            else return INF;
        }
        int mid = s + e >> 1;
        if(sum(s, mid).ma >= 1) return FindLeft(s, mid);
        return FindLeft(mid, e);
    }
};
typedef pair<int,int> P;
int getidx(P n, vector<P> V) {
    return lower_bound(V.begin(),V.end(),n) - V.begin();
}
long long plan_roller_coaster(vector<int> s,vector<int> t) {
    int N = s.size();
    int i;
    vector<P> V;
    for(i=0;i<N;i++) {
        V.push_back(P(s[i],i));
    }
    vector<int> r;
    r.resize(N);
    for(i=0;i<N;i++) {
        r[V[i].second] = i;
    }
    sort(V.begin(),V.end());
    SegTree tree(N + 5);
    int MAX = tree.MAX;
    for(i=0;i<N;i++) {
        tree.seg[i+MAX/2].ma = 1;
        tree.seg[i+MAX/2].sum = 1;
    }
    //cout << "Yes";
    tree.cons();
    int pt = 0;
    for(i=0;i<N-1;i++) {
        tree.Plus(pt, -1);
        //cout << "Minus";
        int s = tree.FindLeft(pt, N);
        //cout << "Find";
        if(s == INF) return 1;
        int e = r[s];
        pt = getidx(P(t[e],-1),V);
    }
    return 0;
}

Compilation message (stderr)

railroad.cpp: In member function 'SegTree::Node SegTree::sum(int, int, int, int, int)':
railroad.cpp:31:22: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   31 |         int mid = ns + ne >> 1;
      |                   ~~~^~~~
railroad.cpp: In member function 'int SegTree::FindLeft(int, int)':
railroad.cpp:60:21: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   60 |         int mid = s + e >> 1;
      |                   ~~^~~

• Subtask 1: 0 / 11
• Subtask 2: 0 / 23
• Subtask 3: 0 / 30
• Subtask 4: 0 / 36