oj.uz

Submission #857170

# Submission time Handle Problem Language Result Execution time Memory
857170 2023-10-05T13:39:03 Z RiverFlow Valley (BOI19_valley) C++14
100 / 100
 142 ms 46244 KB 
#include <bits/stdc++.h>

#define nl "\n"
#define no "NO"
#define yes "YES"
#define fi first
#define se second
#define vec vector
#define task "main"
#define _mp make_pair
#define ii pair<int, int>
#define sz(x) (int)x.size()
#define all(x) x.begin(), x.end()
#define evoid(val) return void(std::cout << val)
#define FOR(i, a, b) for(int i = (a); i <= (b); ++i)
#define FOD(i, b, a) for(int i = (b); i >= (a); --i)
#define unq(x) sort(all(x)); x.resize(unique(all(x)) - x.begin())

using namespace std;

template<typename U, typename V> bool maxi(U &a, V b) {
    if (a < b) { a = b; return 1; } return 0;
}
template<typename U, typename V> bool mini(U &a, V b) {
    if (a > b) { a = b; return 1; } return 0;
}

const int N = (int)2e5 + 9;
const int mod = (int)1e9 + 7;

void prepare(); void main_code();

int main() {
    ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    if (fopen(task".inp", "r")) {
        freopen(task".inp", "r", stdin);
        freopen(task".out", "w", stdout);
    }
    const bool MULTITEST = 0; prepare();
    int num_test = 1; if (MULTITEST) cin >> num_test;
    while (num_test--) { main_code(); }
}

void prepare() {};

int n, s, q, e;

const int LG = 17;

int par[N][LG + 1], h[N];

long long dist[N];

int lca(int u, int v) {
    if (u == v) return u;
    if (h[u] < h[v]) swap(u, v);
    FOD(j, LG, 0) if (h[par[u][j]] >= h[v]) u = par[u][j];
    if (u == v) return u;
    FOD(j, LG, 0) if (par[u][j] != par[v][j])
        u = par[u][j], v = par[v][j];
    return par[u][0];
}

const long long INF = (long long)1e16;

bool shop[N];

long long cshop[N], jmp[N][LG + 1], val[N];

vector<pair<int, int>> g[N];

int _timer = 0, tin[N], tout[N];

void dfs(int u, int p) {
    cshop[u] = INF;
    if (shop[u]) cshop[u] = dist[u];
    for(int j = 1; j <= LG; ++j) {
        par[u][j] = par[ par[u][j - 1] ][j - 1];
    }
    tin[u] = ++_timer;
    for(auto j : g[u]) if (j.fi ^ p) {
        int v = j.fi;
        h[v] = h[u] + 1;
        par[v][0] = u;
        dist[v] = dist[u] + j.se;
        dfs(v, u);
        cshop[u] = min(cshop[u], cshop[v]);
    }
    tout[u] = ++_timer;
}

void dfs2(int u, int p) {
    val[u] = cshop[u] - 2LL * dist[u];
    if (cshop[u] == INF) val[u] = INF;
    jmp[u][0] = min(val[u], val[p]);
    for(int j = 1; j <= LG; ++j) {
        jmp[u][j] = min(jmp[u][j - 1], jmp[par[u][j - 1]][j - 1]);
    }
    for(auto j : g[u]) if (j.fi ^ p) {
        dfs2(j.fi, u);
    }
}

ii E[N];

long long jump(int u, int p) {
    long long res = INF;
    res = min(res, val[u]);
    for(int j = LG; j >= 0; --j) {
        if (h[ par[u][j] ] < h[p]) continue ;
        res = min(res, jmp[u][j]);
        u = par[u][j];
    }
    return res;
}

void main_code() {
    cin >> n >> s >> q >> e;
    for(int i = 1; i < n; ++i) {
        int u, v, w; cin >> u >> v >> w;
        g[u].emplace_back(v, w);
        g[v].emplace_back(u, w);
        E[i] = _mp(u, v);
    }
    for(int i = 1; i <= s; ++i) {
        int x; cin >> x; shop[x] = 1;
    }
    FOR(i, 0, n) FOR(j, 0, LG) jmp[i][j] = INF;
    h[0] = -1; val[0] = INF;
    dfs(e, 0); dfs2(e, 0);
    while (q--) {
        int i, r; cin >> i >> r;
        int u = E[i].fi, v = E[i].se;
        if (h[u] > h[v]) swap(u, v);
        if (tin[v] <= tin[r] and tout[r] <= tout[v]) {
            long long l = jump(r, v);
            if (l == INF) {
                cout << "oo\n";
            } else {
                cout << l + dist[r] << nl;
            }
        } else {
            cout << "escaped\n";
        }
    }
}


/*     Let the river flows naturally     */

Compilation message

valley.cpp: In function 'int main()':
valley.cpp:36:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   36 |         freopen(task".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
valley.cpp:37:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   37 |         freopen(task".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
9.0 / 9.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 14684 KB Output is correct
2 Correct 5 ms 14820 KB Output is correct
3 Correct 4 ms 14684 KB Output is correct
4 Correct 4 ms 14684 KB Output is correct

Subtask #2
27.0 / 27.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 14684 KB Output is correct
2 Correct 5 ms 14820 KB Output is correct
3 Correct 4 ms 14684 KB Output is correct
4 Correct 4 ms 14684 KB Output is correct
5 Correct 3 ms 14940 KB Output is correct
6 Correct 3 ms 14940 KB Output is correct
7 Correct 3 ms 14940 KB Output is correct
8 Correct 3 ms 14940 KB Output is correct
9 Correct 3 ms 14836 KB Output is correct
10 Correct 4 ms 14936 KB Output is correct
11 Correct 4 ms 14940 KB Output is correct
12 Correct 4 ms 14940 KB Output is correct
13 Correct 3 ms 14936 KB Output is correct
14 Correct 3 ms 14940 KB Output is correct

Subtask #3
23.0 / 23.0

# Verdict Execution time Memory Grader output
1 Correct 96 ms 41556 KB Output is correct
2 Correct 110 ms 41288 KB Output is correct
3 Correct 142 ms 41196 KB Output is correct
4 Correct 126 ms 42324 KB Output is correct
5 Correct 114 ms 43000 KB Output is correct
6 Correct 130 ms 44368 KB Output is correct

Subtask #4
41.0 / 41.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 14684 KB Output is correct
2 Correct 5 ms 14820 KB Output is correct
3 Correct 4 ms 14684 KB Output is correct
4 Correct 4 ms 14684 KB Output is correct
5 Correct 3 ms 14940 KB Output is correct
6 Correct 3 ms 14940 KB Output is correct
7 Correct 3 ms 14940 KB Output is correct
8 Correct 3 ms 14940 KB Output is correct
9 Correct 3 ms 14836 KB Output is correct
10 Correct 4 ms 14936 KB Output is correct
11 Correct 4 ms 14940 KB Output is correct
12 Correct 4 ms 14940 KB Output is correct
13 Correct 3 ms 14936 KB Output is correct
14 Correct 3 ms 14940 KB Output is correct
15 Correct 96 ms 41556 KB Output is correct
16 Correct 110 ms 41288 KB Output is correct
17 Correct 142 ms 41196 KB Output is correct
18 Correct 126 ms 42324 KB Output is correct
19 Correct 114 ms 43000 KB Output is correct
20 Correct 130 ms 44368 KB Output is correct
21 Correct 96 ms 41780 KB Output is correct
22 Correct 104 ms 41452 KB Output is correct
23 Correct 103 ms 40532 KB Output is correct
24 Correct 115 ms 43600 KB Output is correct
25 Correct 127 ms 46244 KB Output is correct
26 Correct 121 ms 41812 KB Output is correct
27 Correct 112 ms 41300 KB Output is correct
28 Correct 105 ms 41304 KB Output is correct
29 Correct 111 ms 42580 KB Output is correct
30 Correct 136 ms 43396 KB Output is correct
31 Correct 100 ms 41012 KB Output is correct
32 Correct 101 ms 40728 KB Output is correct
33 Correct 123 ms 41372 KB Output is correct
34 Correct 125 ms 42404 KB Output is correct
35 Correct 120 ms 45968 KB Output is correct
36 Correct 120 ms 43868 KB Output is correct