Submission #342780

#	Time	Username	Problem	Language	Result	Execution time	Memory
342780		spike1236	Valley (BOI19_valley)	C++14	36 / 100	159 ms	18028 KiB

valley

#include <bits/stdc++.h>
using namespace std;
#define pb push_back
#define mp make_pair
#define f first
#define s second
#define ll long long
#define ld long double
#define all(_v) _v.begin(), _v.end()
#define sz(_v) (int)_v.size()
#define pii pair <int, int>
#define pll pair <ll, ll>
#define veci vector <int>
#define vecll vector <ll>


const int dx[4] = {1, -1, 0, 0};
const int dy[4] = {0, 0, -1, 1};
const double PI = 3.1415926535897932384626433832795;
const double eps = 1e-9;
const int MOD1 = 1e9 + 7;
const int MOD2 = 998244353;

const int MAXN = 1e5 + 10;
int root, tmr;
int tin[MAXN], tout[MAXN];
set <pii> g[MAXN];
pii EDGE[MAXN];
int shop[MAXN], is_shop[MAXN];
pii query[MAXN];
int n, s, q;

void dfs_calc(int v = root, int p = 0) {
    tin[v] = ++tmr;
    for(auto to : g[v])
        if(to.f != p)
            dfs_calc(to.f, v);
    tout[v] = ++tmr;
}

bool upper(int v, int u) {
    return (tin[v] <= tin[u] && tout[v] >= tout[u]);
}

ll res_sub12;

void dfs_sub12(int v, int p, int blu, int blv, ll sum) {
    if(is_shop[v]) res_sub12 = min(res_sub12, sum);
    for(auto to : g[v]) {
        if(to.f != p)
            if(v == blu && to.f == blv) continue;
            else dfs_sub12(to.f, v, blu, blv, sum + to.s);
    }
}

void sub12() {
    for(int i = 1; i <= q; ++i) {
        int blv = EDGE[query[i].f].f, blu = EDGE[query[i].f].s, v = query[i].s;
        if(!upper(blv, blu)) swap(blv, blu);
        if(upper(blu, v)) {
            res_sub12 = 1e18;
            dfs_sub12(v, 0, blu, blv, 0);
            if(res_sub12 == 1e18) cout << "oo\n";
            else cout << res_sub12 << '\n';
        } else cout << "escaped\n";
    }
    exit(0);
}

void sub3() {
    for(int i = 1; i <= q; ++i) {
        int blv = EDGE[query[i].f].f, blu = EDGE[query[i].f].s, v = query[i].s;
        if(!upper(blv, blu)) swap(blv, blu);
        if(upper(blu, v)) cout << 0;
        else cout << "escaped\n";
    }
    exit(0);
}

void solve() {
    cin >> n >> s >> q >> root;
    for(int i = 1; i < n; ++i) {
        int u, v, cost;
        cin >> u >> v >> cost;
        g[u].insert(mp(v, cost));
        g[v].insert(mp(u, cost));
        EDGE[i] = mp(u, v);
    }
    for(int i = 1; i <= s; ++i)
        cin >> shop[i], is_shop[shop[i]] = 1;
    for(int i = 1; i <= q; ++i)
        cin >> query[i].f >> query[i].s;
    dfs_calc();
    if((n <= 100 && q <= 10000) || (n <= 1000 && q <= 1000)) sub12();
    if(s == n) sub3();
}


int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    int T = 1;
    ///cin >> T;
    while(T--) solve(), cout << '\n';
    return 0;
}

Compilation message (stderr)

valley.cpp: In function 'void dfs_sub12(int, int, int, int, long long int)':
valley.cpp:50:11: warning: suggest explicit braces to avoid ambiguous 'else' [-Wdangling-else]
   50 |         if(to.f != p)
      |           ^

• Subtask 1: 9 / 9
• Subtask 2: 27 / 27
• Subtask 3: 0 / 23
• Subtask 4: 0 / 41