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Submission #118768

# Submission time Handle Problem Language Result Execution time Memory
118768 2019-06-19T16:52:45 Z someone_aa Highway Tolls (IOI18_highway) C++17
51 / 100
 374 ms 24672 KB 
#include "highway.h"
#include <bits/stdc++.h>
#define ll long long
#define pb push_back
#define mp make_pair
using namespace std;
const int maxn = 150100;
int n, m;
vector<int>w;
vector<int>gs[maxn];
vector<pair<int,int> > g[maxn];

vector<int>gt[maxn];

int dist[maxn][2], parent[maxn][2];
int pind[maxn];
bool visited[maxn];

ll dista;

map<pair<int,int>, int> ind;
int type[maxn];
vector<pair<int,int> > sta, stb;
bool important[maxn];

void bfs(int u, int v) {
    visited[u] = visited[v] = true;
    queue<pair<int,int> > q;

    type[u] = 0;
    type[v] = 1;
    q.push(mp(u, 0));
    q.push(mp(v, 1));

    pind[u] = pind[v] = -1;

    while(!q.empty()) {
        int curr = q.front().first;
        int currtype = q.front().second;
        q.pop();

        for(auto i:g[curr]) {
            int ni = i.first;
            int nind = i.second;
            if(visited[ni]) continue;
            visited[ni] = true;
            type[ni] = currtype;
            pind[ni] = nind;

            important[nind] = true;

            q.push(mp(ni, currtype));
        }
    }
}

int solve(int root, int d) {
    // build bfs tree
    memset(visited,false,sizeof(visited));
    //memset(parent,-1,sizeof(parent));

    vector<int>v, v2, vind;

    queue<int>q;
    q.push(root);

    visited[root] = true;
    parent[root][d] = -1;

    while(!q.empty()) {
        int curr = q.front();
        q.pop();

        v.pb(parent[curr][d]);
        v2.pb(curr);
        vind.pb(pind[curr]);

        for(auto i:gs[curr]) {
            if(!visited[i] && type[i] == type[curr]) {
                visited[i] = true;
                parent[i][d] = curr;
                dist[i][d] = dist[curr][d] + 1;
                q.push(i);
            }
        }
    }

    if(v.size() == 1) return v2[0];
    // perform binary search

    for(int i=0;i<v.size();i++) {
        if(v[i] == -1) continue; // root
        int cind = vind[i];
        w[cind] = 1;
    }

    for(int i=0;i<m;i++) {
        if(!important[i]) w[i] = 1;
    }

    int li = 0, ri = v.size() - 1;

    while(li < ri) {
        int mid = (li + ri) / 2;

        // all before mid put them as low cost and other as high cost
        for(int i=0;i<=mid;i++) {
            if(v[i] == -1) continue; // root
            int cind = vind[i];
            w[cind] = 0;
        }

        ll cdist = ask(w);
        for(int i=0;i<=mid;i++) {
            if(v[i] == -1) continue; // root
            int cind = vind[i];
            w[cind] = 1;
        }

        if(cdist == dista) {
            ri = mid;
        }
        else {
            li = mid + 1;
        }
    }

    for(int i=0;i<v.size();i++) {
        if(v[i] == -1) continue; // root
        int cind = vind[i];
        w[cind] = 0;
    }

    for(int i=0;i<m;i++) {
        if(!important[i]) w[i] = 0;
    }

    return v2[li];
}

void find_pair(int N, std::vector<int> U, std::vector<int> V, int A, int B) {
    n = N; m = U.size();
    int li=0, ri=m-1;

    for(int i=0;i<m;i++) {
        //ind[mp(U[i], V[i])] = ind[mp(V[i], U[i])] = i;
        gs[U[i]].pb(V[i]);
        gs[V[i]].pb(U[i]);

        g[U[i]].pb(mp(V[i], i));
        g[V[i]].pb(mp(U[i], i));

        w.pb(0);
    }

    dista = ask(w);
    while(li<ri) {
        int mid = (li+ri)/2;
        for(int i=li;i<=mid;i++) {
            w[i] = 1;
        }
        ll distb = ask(w);
        for(int i=li;i<=mid;i++) {
            w[i] = 0;
        }

        if(dista == distb) {
            li = mid + 1;
        }
        else {
            ri = mid;
        }
    }

    int x = li;
    int u = U[x], v = V[x];
    important[x] = true;

    //cout<<u<<" "<<v<<"\n";

    bfs(u, v);
    //preprocess();

    //memset(visited,false,sizeof(visited));
    //cout<<"Ans: "<<xx<<" "<<yy<<"\n";
    answer(solve(u, 0), solve(v, 1));
}

Compilation message

highway.cpp: In function 'int solve(int, int)':
highway.cpp:91:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0;i<v.size();i++) {
                 ~^~~~~~~~~
highway.cpp:128:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0;i<v.size();i++) {
                 ~^~~~~~~~~

Subtask #1
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 12 ms 11000 KB Output is correct
2 Correct 12 ms 11048 KB Output is correct
3 Correct 12 ms 11008 KB Output is correct
4 Correct 12 ms 11000 KB Output is correct
5 Correct 12 ms 11040 KB Output is correct
6 Correct 12 ms 11044 KB Output is correct
7 Correct 12 ms 11048 KB Output is correct
8 Correct 12 ms 11040 KB Output is correct
9 Correct 12 ms 11028 KB Output is correct
10 Correct 12 ms 11000 KB Output is correct
11 Correct 11 ms 11044 KB Output is correct
12 Correct 12 ms 11048 KB Output is correct

Subtask #2
7.0 / 7.0

# Verdict Execution time Memory Grader output
1 Correct 13 ms 11128 KB Output is correct
2 Correct 35 ms 12316 KB Output is correct
3 Correct 266 ms 23204 KB Output is correct
4 Correct 271 ms 22820 KB Output is correct
5 Correct 299 ms 22824 KB Output is correct
6 Correct 280 ms 23112 KB Output is correct
7 Correct 254 ms 22816 KB Output is correct
8 Correct 258 ms 22808 KB Output is correct
9 Correct 238 ms 22860 KB Output is correct
10 Correct 256 ms 22888 KB Output is correct
11 Correct 354 ms 21712 KB Output is correct
12 Correct 338 ms 22264 KB Output is correct
13 Correct 302 ms 22392 KB Output is correct
14 Correct 232 ms 22364 KB Output is correct

Subtask #3
6.0 / 6.0

# Verdict Execution time Memory Grader output
1 Correct 31 ms 12264 KB Output is correct
2 Correct 51 ms 13356 KB Output is correct
3 Correct 66 ms 14748 KB Output is correct
4 Correct 172 ms 21484 KB Output is correct
5 Correct 191 ms 21480 KB Output is correct
6 Correct 191 ms 22004 KB Output is correct
7 Correct 170 ms 22384 KB Output is correct
8 Correct 193 ms 21288 KB Output is correct
9 Correct 195 ms 22252 KB Output is correct

Subtask #4
33.0 / 33.0

# Verdict Execution time Memory Grader output
1 Correct 13 ms 11132 KB Output is correct
2 Correct 36 ms 12408 KB Output is correct
3 Correct 185 ms 20540 KB Output is correct
4 Correct 243 ms 22824 KB Output is correct
5 Correct 259 ms 22784 KB Output is correct
6 Correct 270 ms 22816 KB Output is correct
7 Correct 258 ms 22824 KB Output is correct
8 Correct 267 ms 22808 KB Output is correct
9 Correct 263 ms 22796 KB Output is correct
10 Correct 255 ms 22844 KB Output is correct
11 Correct 274 ms 22408 KB Output is correct
12 Correct 292 ms 22328 KB Output is correct
13 Correct 288 ms 22272 KB Output is correct
14 Correct 240 ms 21736 KB Output is correct
15 Correct 248 ms 22916 KB Output is correct
16 Correct 212 ms 22948 KB Output is correct
17 Correct 295 ms 22368 KB Output is correct
18 Correct 271 ms 22384 KB Output is correct
19 Correct 270 ms 22816 KB Output is correct
20 Correct 253 ms 22476 KB Output is correct
21 Correct 201 ms 23860 KB Output is correct
22 Correct 228 ms 23864 KB Output is correct
23 Correct 215 ms 22808 KB Output is correct
24 Correct 202 ms 22732 KB Output is correct
25 Correct 249 ms 22524 KB Output is correct

Subtask #5
0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 40 ms 12376 KB Output is correct
2 Correct 33 ms 12420 KB Output is correct
3 Correct 328 ms 23176 KB Output is correct
4 Correct 304 ms 23644 KB Output is correct
5 Correct 374 ms 24168 KB Output is correct
6 Incorrect 339 ms 24672 KB Output is incorrect: {s, t} is wrong.
7 Halted 0 ms 0 KB -

Subtask #6
0 / 31.0

# Verdict Execution time Memory Grader output
1 Correct 38 ms 12368 KB Output is correct
2 Correct 57 ms 12392 KB Output is correct
3 Correct 289 ms 22660 KB Output is correct
4 Incorrect 314 ms 23368 KB Output is incorrect: {s, t} is wrong.
5 Halted 0 ms 0 KB -