oj.uz

Submission #131550

# Submission time Handle Problem Language Result Execution time Memory
131550 2019-07-17T09:26:50 Z SamAnd One-Way Streets (CEOI17_oneway) C++17
100 / 100
 456 ms 46840 KB 
#include <bits/stdc++.h>
using namespace std;
#define m_p make_pair
const int N = 100005, l = 20;

int n, m;
pair<int, int> r[N];
vector<int> a[N];
vector<int> b[N];

bool bri[N];

int c[N];
int tin[N], ti, fup[N];
void dfs0(int x, int p)
{
    c[x] = 1;
    fup[x] = tin[x] = ti++;
    for (int i = 0; i < a[x].size(); ++i)
    {
        int h = a[x][i];
        if (h == p)
            continue;
        if (c[h])
            fup[x] = min(fup[x], tin[h]);
        else
        {
            dfs0(h, x);
            if (fup[h] > tin[x])
                bri[b[x][i]] = true;
            fup[x] = min(fup[x], fup[h]);
        }
    }
}

int k;
void dfs1(int x)
{
    c[x] = k;
    for (int i = 0; i < a[x].size(); ++i)
    {
        if (bri[b[x][i]])
            continue;
        int h = a[x][i];
        if (!c[h])
            dfs1(h);
    }
}

vector<int> g[N];
vector<int> gg[N];
bool c1[N];
int tout[N];
int pp[N][l];
bool dfs(int x, int p)
{
    c1[x] = true;
    tin[x] = ti++;
    pp[x][0] = p;
    for (int i = 1; i < l; ++i)
    {
        pp[x][i] = pp[pp[x][i - 1]][i - 1];
    }
    for (int i = 0; i < g[x].size(); ++i)
    {
        int h = g[x][i];
        if (h == p)
            continue;
        dfs(h, x);
    }
    tout[x] = ti++;
}
bool par(int x, int y)
{
    return (tin[x] <= tin[y] && tout[x] >= tout[y]);
}
int lca(int x, int y)
{
    if (par(x, y))
        return x;
    if (par(y, x))
        return y;
    for (int i = l - 1; i >= 0; --i)
    {
        if (!par(pp[x][i], y))
            x = pp[x][i];
    }
    return pp[x][0];
}

char ans[N];

int qu[N], qd[N];
void dfsf(int x, int p, int j)
{
    for (int i = 0; i < g[x].size(); ++i)
    {
        int h = g[x][i];
        if (h == p)
            continue;
        dfsf(h, x, gg[x][i]);
        qu[x] += qu[h];
        qd[x] += qd[h];
    }
    if (qu[x])
    {
        if (m_p(x, p) == m_p(c[r[j].first], c[r[j].second]))
            ans[j - 1] = 'R';
        else
            ans[j - 1] = 'L';
    }
    if (qd[x])
    {
        if (m_p(p, x) == m_p(c[r[j].first], c[r[j].second]))
            ans[j - 1] = 'R';
        else
            ans[j - 1] = 'L';
    }
}

int main()
{
    //freopen("input.txt", "r", stdin);
    map<pair<int, int> , int> mp;
    scanf("%d%d", &n, &m);
    for (int i = 1; i <= m; ++i)
    {
        int x, y;
        scanf("%d%d", &x, &y);
        a[x].push_back(y);
        a[y].push_back(x);
        b[x].push_back(i);
        b[y].push_back(i);
        r[i] = m_p(x, y);
        if (x > y)
            swap(x, y);
        mp[m_p(x, y)]++;
    }

    for (int i = 1; i <= n; ++i)
    {
        if (!c[i])
            dfs0(i, -1);
    }
    for (int i = 1; i <= m; ++i)
    {
        if (bri[i])
        {
            if (mp[m_p(min(r[i].first, r[i].second), max(r[i].first, r[i].second))] > 1)
                bri[i] = false;
        }
    }
    memset(c, 0, sizeof c);
    for (int x = 1; x <= n; ++x)
    {
        if (!c[x])
        {
            ++k;
            dfs1(x);
        }
    }
    for (int x = 1; x <= n; ++x)
    {
        for (int i = 0; i < a[x].size(); ++i)
        {
            if (bri[b[x][i]])
            {
                g[c[x]].push_back(c[a[x][i]]);
                gg[c[x]].push_back(b[x][i]);
            }
        }
    }

    for (int i = 1; i <= m; ++i)
        ans[i - 1] = 'B';

    vector<int> v;
    for (int i = 1; i <= k; ++i)
    {
        if (!c1[i])
        {
            v.push_back(i);
            dfs(i, i);
        }
    }

    int q;
    scanf("%d", &q);
    while (q--)
    {
        int x, y;
        scanf("%d%d", &x, &y);
        x = c[x];
        y = c[y];
        int t = lca(x, y);
        qu[x]++;
        qu[t]--;
        qd[y]++;
        qd[t]--;
    }
    for (int i = 0; i < v.size(); ++i)
    {
        dfsf(v[i], v[i], -1);
    }
    cout << ans << endl;
    return 0;
}

Compilation message

oneway.cpp: In function 'void dfs0(int, int)':
oneway.cpp:19:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i = 0; i < a[x].size(); ++i)
                     ~~^~~~~~~~~~~~~
oneway.cpp: In function 'void dfs1(int)':
oneway.cpp:40:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i = 0; i < a[x].size(); ++i)
                     ~~^~~~~~~~~~~~~
oneway.cpp: In function 'bool dfs(int, int)':
oneway.cpp:64:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i = 0; i < g[x].size(); ++i)
                     ~~^~~~~~~~~~~~~
oneway.cpp:72:1: warning: no return statement in function returning non-void [-Wreturn-type]
 }
 ^
oneway.cpp: In function 'void dfsf(int, int, int)':
oneway.cpp:96:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i = 0; i < g[x].size(); ++i)
                     ~~^~~~~~~~~~~~~
oneway.cpp: In function 'int main()':
oneway.cpp:164:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (int i = 0; i < a[x].size(); ++i)
                         ~~^~~~~~~~~~~~~
oneway.cpp:201:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i = 0; i < v.size(); ++i)
                     ~~^~~~~~~~~~
oneway.cpp:125:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d%d", &n, &m);
     ~~~~~^~~~~~~~~~~~~~~~
oneway.cpp:129:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d%d", &x, &y);
         ~~~~~^~~~~~~~~~~~~~~~
oneway.cpp:188:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d", &q);
     ~~~~~^~~~~~~~~~
oneway.cpp:192:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d%d", &x, &y);
         ~~~~~^~~~~~~~~~~~~~~~

Subtask #1
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 11 ms 10104 KB Output is correct
2 Correct 11 ms 10104 KB Output is correct
3 Correct 12 ms 10232 KB Output is correct
4 Correct 12 ms 10488 KB Output is correct
5 Correct 13 ms 10488 KB Output is correct
6 Correct 12 ms 10232 KB Output is correct
7 Correct 12 ms 10488 KB Output is correct
8 Correct 12 ms 10420 KB Output is correct
9 Correct 12 ms 10232 KB Output is correct
10 Correct 12 ms 10232 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 11 ms 10104 KB Output is correct
2 Correct 11 ms 10104 KB Output is correct
3 Correct 12 ms 10232 KB Output is correct
4 Correct 12 ms 10488 KB Output is correct
5 Correct 13 ms 10488 KB Output is correct
6 Correct 12 ms 10232 KB Output is correct
7 Correct 12 ms 10488 KB Output is correct
8 Correct 12 ms 10420 KB Output is correct
9 Correct 12 ms 10232 KB Output is correct
10 Correct 12 ms 10232 KB Output is correct
11 Correct 159 ms 22904 KB Output is correct
12 Correct 182 ms 24144 KB Output is correct
13 Correct 233 ms 26104 KB Output is correct
14 Correct 285 ms 30596 KB Output is correct
15 Correct 288 ms 32476 KB Output is correct
16 Correct 361 ms 41464 KB Output is correct
17 Correct 334 ms 42736 KB Output is correct
18 Correct 456 ms 41464 KB Output is correct
19 Correct 336 ms 44024 KB Output is correct
20 Correct 181 ms 24056 KB Output is correct
21 Correct 147 ms 23676 KB Output is correct

Subtask #3
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 11 ms 10104 KB Output is correct
2 Correct 11 ms 10104 KB Output is correct
3 Correct 12 ms 10232 KB Output is correct
4 Correct 12 ms 10488 KB Output is correct
5 Correct 13 ms 10488 KB Output is correct
6 Correct 12 ms 10232 KB Output is correct
7 Correct 12 ms 10488 KB Output is correct
8 Correct 12 ms 10420 KB Output is correct
9 Correct 12 ms 10232 KB Output is correct
10 Correct 12 ms 10232 KB Output is correct
11 Correct 159 ms 22904 KB Output is correct
12 Correct 182 ms 24144 KB Output is correct
13 Correct 233 ms 26104 KB Output is correct
14 Correct 285 ms 30596 KB Output is correct
15 Correct 288 ms 32476 KB Output is correct
16 Correct 361 ms 41464 KB Output is correct
17 Correct 334 ms 42736 KB Output is correct
18 Correct 456 ms 41464 KB Output is correct
19 Correct 336 ms 44024 KB Output is correct
20 Correct 181 ms 24056 KB Output is correct
21 Correct 147 ms 23676 KB Output is correct
22 Correct 411 ms 43888 KB Output is correct
23 Correct 404 ms 42360 KB Output is correct
24 Correct 436 ms 42780 KB Output is correct
25 Correct 413 ms 46840 KB Output is correct
26 Correct 418 ms 43592 KB Output is correct
27 Correct 405 ms 42488 KB Output is correct
28 Correct 82 ms 14772 KB Output is correct
29 Correct 214 ms 24796 KB Output is correct
30 Correct 204 ms 24952 KB Output is correct
31 Correct 223 ms 25128 KB Output is correct
32 Correct 246 ms 30540 KB Output is correct