Submission #770196

#	Time	Username	Problem	Language	Result	Execution time	Memory
770196		PurpleCrayon	Constellation 3 (JOI20_constellation3)	C++17	35 / 100	1582 ms	53624 KiB

constellation3

#include <bits/stdc++.h>
using namespace std;

#define sz(v) int(v.size())
#define ar array
typedef long long ll;
const int N = 2e5+10, MOD = 998244353;
const int L = 18;

struct FT {
    vector<ll> bit;
    FT() {}
    FT(int n) {
        bit.resize(n);
    }

    void upd(int i, int x) {
        for (; i < sz(bit); i |= i+1) bit[i] += x;
    }

    ll qry(int i) {
        ll ans = 0;
        for (++i; i > 0; i &= i-1) ans += bit[i-1];
        return ans;
    }
} bit;

int n, m, a[N], st[N], en[N], bro[N], anc[N][L];
int par[N];
vector<int> child[N];
vector<pair<int, ll>> can[N];
ll dp[N];

int tt = 0;
void dfs_st(int c) {
    st[c] = tt++;
    for (int nxt : child[c]) {
        dfs_st(nxt);
    }
    en[c] = tt-1;
}

void build_tree() {
    memset(par, -1, sizeof(par));
    vector<int> st;
    for (int i = 0; i < n; i++) {
        int last = -1;
        while (sz(st) && a[st.back()] < a[i]) {
            last = st.back();
            st.pop_back();
        }

        if (sz(st)) par[i] = st.back();
        if (last != -1) par[last] = i;
        st.push_back(i);
    }
}

ll f(int bot, int top) {
    // return bit.qry(st[bot]) - bit.qry(st[top]);
    if (bot == top) return 0;
    return dp[bro[bot]] + f(par[bot], top);
}

void dfs(int c) {
    for (int nxt : child[c]) {
        dfs(nxt);
    }
    for (int nxt : child[c]) {
        bit.upd(st[nxt], dp[bro[nxt]]);
        bit.upd(en[nxt]+1, -dp[bro[nxt]]);
    }

    dp[c] = 0;
    for (int nxt : child[c]) dp[c] += dp[nxt];
    for (auto [v, x] : can[c]) {
        ll cur = x + f(v, c);
        for (int nxt : child[v]) cur += dp[nxt];
        dp[c] = max(dp[c], cur);
    }
}

void solve() {
    cin >> n;
    for (int i = 0; i < n; i++) cin >> a[i];

    bit = FT(n);
    build_tree();
    int root = -1;
    for (int i = 0; i < n; i++) {
        if (par[i] == -1) {
            root = i;
        }
    }
    for (int i = 0; i < n; i++) if (i != root) {
        child[par[i]].push_back(i);
    }

    memset(bro, -1, sizeof(bro));
    for (int i = 0; i < n; i++) if (i != root) {
        for (int nxt : child[par[i]]) if (nxt != i) {
            bro[i] = nxt;
        }
    }
    
    dfs_st(root);

    for (int i = 0; i < n; i++) {
        anc[i][0] = par[i];
    }

    for (int k = 1; k < L; k++) {
        for (int i = 0; i < n; i++) {
            anc[i][k] = anc[i][k-1] == -1 ? -1 : anc[anc[i][k-1]][k-1];
        }
    }

    cin >> m;
    ll base = 0;
    for (int i = 0; i < m; i++) {
        int x, y; ll c; cin >> x >> y >> c, --x; base += c;

        int top = x;
        for (int k = L-1; k >= 0; k--) {
            if (anc[top][k] != -1 && a[anc[top][k]] < y) {
                top = anc[top][k];
            }
        }

        can[top].push_back({x, c});
    }


    dfs(root);
    cout << base - dp[root] << '\n';
}

int main() {
    ios::sync_with_stdio(false); cin.tie(0);
    int T = 1;
    // cin >> T;
    while (T--) solve();
}

• Subtask 1: 14 / 14
• Subtask 2: 21 / 21
• Subtask 3: 0 / 65