Submission #1099384

#	Time	Username	Problem	Language	Result	Execution time	Memory
1099384		RiverFlow	Magic Tree (CEOI19_magictree)	C++14	47 / 100	2095 ms	33108 KiB

magictree

#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, m, k;

int s[N], y[N], re[N];
pair<int, int> a[N];
vector<int> g[N], adj[N];

int cnt = 0;

void dfs(int u) {
    s[u] = y[u];
    vec<int> c;
    for(int v : g[u]) {
        dfs(v);
        s[u] += s[v];
        if (s[v] > 0) {
            c.push_back(v);
        }
    }
    if (!y[u] and sz(c) == 0) {
        re[u] = -1;
        return ;
    }
    if (!y[u]) {
        if (sz(c) == 1) {
            re[u] = re[c.back()];
            return ;
        }
        re[u] = u;
        for(int v : c)
            adj[u].push_back(re[v]);
        return ;
    }
    re[u] = u;
    for(int v : c)
        adj[u].push_back(re[v]);
}

bool on[N];

long long dp[N];

void dfx(int u, int d, long long &c) {
    if (on[u]) {
        c += dp[u];
        return ;
    }
    for(int v : adj[u]) {
        dfx(v, d, c);
    }
}
void dfs2(int u, int D) {
    long long s = 0;
    for(int v : adj[u]) {
        dfs2(v, D);
        s += dp[v];
    }
    maxi(dp[u], s);
    long long nw = 0;
    if (y[u] and a[u].fi == D) {
        dfx(u, a[u].first, nw);
        maxi(dp[u], nw + a[u].se);
    }

    if (a[u].fi == D)
        on[u] = 1;
}
void main_code() {
    cin >> n >> m >> k;
    for(int i = 2; i <= n; ++i) {
        int x; cin >> x;
        g[x].push_back(i);
    }
    y[1] = 1; a[1] = _mp(k + 1, 0);
    vec<bool> ex(k + 1, 0);
    for(int i = 1; i <= m; ++i) {
        int v, d, w; cin >> v >> d >> w;
        y[v] = 1;
        a[v] = _mp(d, w);
        ex[d] = 1;
    }
    dfs(1);
    for(int i = 1; i <= k; ++i) if (ex[i]) {
        dfs2(1, i);
    }
    cout << dp[1];

}


/*     Let the river flows naturally     */

Compilation message (stderr)

magictree.cpp: In function 'int main()':
magictree.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);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
magictree.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: 6 / 6
• Subtask 2: 0 / 3
• Subtask 3: 0 / 11
• Subtask 4: 12 / 12
• Subtask 5: 16 / 16
• Subtask 6: 13 / 13
• Subtask 7: 0 / 22
• Subtask 8: 0 / 17