Submission #811083

#	Time	Username	Problem	Language	Result	Execution time	Memory
811083		Wael	Rail (IOI14_rail)	C++14	30 / 100	51 ms	732 KiB

rail

#include<bits/stdc++.h>
using namespace std;
#include "rail.h"
#define F first
#define S second
typedef int ll;
int const M = 5e3 + 20;
int Dis[M][M] , mn[M] , closer[M] , cur , n;
bool vis[M];
set<ll>TypeC , TypeD;

bool cmp(int a , int  b) {
    return (Dis[0][a] < Dis[0][b]);
}

void findLocation(int n , int first , int location[], int stype[]) {
    int a = 0 , b , MinDis = 1e9;
    location[a] = first;
    stype[a] = 1;
    TypeC.insert(location[a]);

    for(int station = 1 ; station < n ; ++station) {
        Dis[a][station] = getDistance(a , station);
        if(Dis[a][station] < MinDis) {
            b = station;
            MinDis = Dis[a][b];
        }
    }
    location[b] = location[a] + Dis[a][b];
    stype[b] = 2;
    TypeD.insert(location[b]);

    vector<ll>rem;
    for(int station = 1 ; station < n ; ++station) {
        if(station == b) continue;
        Dis[b][station] = getDistance(b , station);
        rem.push_back(station);
    }
    
    sort(rem.begin() , rem.end() , cmp);

    int LeftMost = a , RightMost = b;

    for(int station : rem) { 
        if(Dis[a][station] < Dis[b][station]) {
            int CurDis = getDistance(RightMost , station);
            //int CurDis = dis(RightMost , station);
            int Expect = location[RightMost] - CurDis;
            auto it = TypeD.lower_bound(Expect);
            if(*it - location[a] + *it - Expect == Dis[a][station] && Expect > location[b]) {
                //assert(stype[station] == 1);
                location[station] = Expect;
                stype[station] = 1;
                TypeC.insert(location[station]);
            } else {
                //assert(stype[station] == 2);
                RightMost = station;
                location[RightMost] = location[a] + Dis[a][RightMost];
                stype[RightMost] = 2;
                TypeD.insert(location[RightMost]);
            }
        }

        else {
            int CurDis = getDistance(LeftMost , station);
            //int CurDis = dis(LeftMost , station);
            int Expect = location[LeftMost] + CurDis;
            auto it = TypeC.upper_bound(Expect); --it;
            if(location[b] - *it + Expect - *it == Dis[b][station] && Expect < location[a]) {
                //assert(stype[station] == 2);
                location[station] = Expect;
                stype[station] = 2;
                TypeD.insert(location[station]);
            } else {
                //assert(stype[station] == 1);
                LeftMost = station;
                location[LeftMost] = location[b] - Dis[b][LeftMost];
                stype[LeftMost] = 1;
                TypeC.insert(location[LeftMost]);
            }
        }
    }
/*
    map<ll , ll>cnt;
    int ok = 1;
    for(int i = 0 ; i < n ; ++i) {
        ++cnt[location[i]];
        if(cnt[location[i]] > 1) ok = 0;
        assert(location[i] >= 0);
    }
    assert(ok);
*/
    return;
}
/*
2
6
1 4
2 5
2 6
2 7
1 1
2 2
*/

Compilation message (stderr)

rail.cpp: In function 'void findLocation(int, int, int*, int*)':
rail.cpp:45:44: warning: 'b' may be used uninitialized in this function [-Wmaybe-uninitialized]
   45 |         if(Dis[a][station] < Dis[b][station]) {
      |                              ~~~~~~~~~~~~~~^

• Subtask 1: 8 / 8
• Subtask 2: 22 / 22
• Subtask 3: 0 / 26
• Subtask 4: 0 / 44