Submission #170216

#	Time	Username	Problem	Language	Result	Execution time	Memory
170216		alexandra_udristoiu	Highway Tolls (IOI18_highway)	C++14	100 / 100	360 ms	13224 KiB

highway

#include<iostream>
#include<vector>
#include<algorithm>
#include "highway.h"
#define f first
#define s second
#define DIM 130005
using namespace std;
static int t[2][DIM], niv[2][DIM], viz[2][DIM], m, p[2][DIM], nr[2], n, cd[DIM];
static pair<int, int> w[DIM], aux[DIM];
static vector<int> r, v[DIM];
void bfs(int i, int srs){
   int st, dr, j, nod, vecin;
   viz[i][srs] = 1;
   cd[1] = srs;
   st = dr = 1;
   while(st <= dr){
        nod = cd[st];
        st++;
        for(j = 0; j < v[nod].size(); j++){
            vecin = v[nod][j];
            if(viz[i][vecin] == 0){
                cd[++dr] = vecin;
                niv[i][vecin] = 1 + niv[i][nod];
                t[i][vecin] = nod;
                viz[i][vecin] = 1;
            }
        }
   }
}
int solve(int ind, long long sum){
    int i, st, dr, mid, nr;
    nr = 0;
    for(i = 1; i <= n; i++){
        if(niv[ind][i] < niv[1 - ind][i]){
            aux[++nr] = make_pair(niv[ind][i], i);
        }
    }
    sort(aux + 1, aux + nr + 1);
    for(i = 1; i <= nr; i++){
        p[ind][ aux[i].s ] = i;
    }
    st = 1;
    dr = nr;
    while(st <= dr){
        mid = (st + dr) / 2;
        for(i = 0; i < m; i++){
            r[i] = 0;
            if(p[ind][ w[i].f ] > mid || p[ind][ w[i].s ] > mid){
                r[i] = 1;
            }
        }
        if(ask(r) == sum){
            dr = mid - 1;
        }
        else{
            st = mid + 1;
        }
    }
    return aux[st].s;
}
void find_pair(int N, vector<int> U, vector<int> V, int a, int b){
    n = N;
    int i, st, dr, mid, x, y;
    long long sum, cost;
    m = U.size();
    r.resize(m);
    for(i = 0; i < m; i++){
        w[i] = make_pair(U[i] + 1, V[i] + 1);
        v[ w[i].f ].push_back(w[i].s);
        v[ w[i].s ].push_back(w[i].f);
        r[i] = 0;
    }
    sum = ask(r);
    st = 1;
    dr = m;
    while(st <= dr){
        mid = (st + dr) / 2;
        for(i = 0; i < m; i++){
            if(i < mid){
                r[i] = 0;
            }
            else{
                r[i] = 1;
            }
        }
        if(ask(r) == sum){
            dr = mid - 1;
        }
        else{
            st = mid + 1;
        }
    }
    bfs(0, w[dr].f);
    bfs(1, w[dr].s);
    x = solve(0, sum);
    y = solve(1, sum);
    answer(x - 1, y - 1);
}

Compilation message (stderr)

highway.cpp: In function 'void bfs(int, int)':
highway.cpp:20:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for(j = 0; j < v[nod].size(); j++){
                    ~~^~~~~~~~~~~~~~~
highway.cpp: In function 'void find_pair(int, std::vector<int>, std::vector<int>, int, int)':
highway.cpp:65:20: warning: unused variable 'cost' [-Wunused-variable]
     long long sum, cost;
                    ^~~~
highway.cpp: At global scope:
highway.cpp:9:63: warning: 'nr' defined but not used [-Wunused-variable]
 static int t[2][DIM], niv[2][DIM], viz[2][DIM], m, p[2][DIM], nr[2], n, cd[DIM];
                                                               ^~

• Subtask 1: 5 / 5
• Subtask 2: 7 / 7
• Subtask 3: 6 / 6
• Subtask 4: 33 / 33
• Subtask 5: 18 / 18
• Subtask 6: 31 / 31