Submission #486752

#	Time	Username	Problem	Language	Result	Execution time	Memory
486752		Nimbostratus	Sjekira (COCI20_sjekira)	C++17	40 / 110	69 ms	37320 KiB

sjekira

#include "bits/stdc++.h"
#define endl '\n'
constexpr int maxn = 1e5+5;
constexpr int mod = 1e9+7;
using namespace std;
using lint = long long;
constexpr lint maxk = 1e9;
constexpr lint inf = 1e18;
using pll = pair<lint, lint>;
 
int n;
lint val[maxn];
vector<int> adj[maxn];
set<pll> s;
int m, h;
int tin[maxn], tout[maxn], b[maxn], p[maxn];
lint t[4 * maxn], lz[2 * maxn];
bool vis[maxn];
lint ans;
     
void dfs(int u) {
    b[m] = u;
    tin[u] = m;
    m++;
    for(int v : adj[u])
        if(v != p[u]) {
            p[v] = u;
            dfs(v);
        }
    b[m] = u;
    tout[u] = m;
    m++;
    s.insert({val[u], tin[u]});
}
     
void build() {
    h = 8 * sizeof(int) - __builtin_clz(m);
    for(int i = 0; i < m; i++)
        t[m + i] = val[b[i]];
    for(int i = m - 1; i >= 1; i--) {
        t[i] = max(t[i << 1], t[i << 1 | 1]);
        lz[i] = 1;
    }
}
 
void apply(int u, lint val) {
    t[u] *= val;
    if(u < m)
        lz[u] *= val;
}
     
void fixup(int u) {
    for(u >>= 1; u; u >>= 1)
        t[u] = max(t[u << 1], t[u << 1 | 1]) * lz[u];
}
     
void push(int u) {
    for(int k = h; k > 0; k--) {
        int p = u >> k;
        if(!p)
            continue;        
        apply(p << 1, lz[p]);
        apply(p << 1 | 1, lz[p]);
        lz[p] = 1;
    }
}
     
void update(int l, int r, lint val) {
    l += m;
    r += m;
    int l0 = l, r0 = r;
    for(; l <= r; l >>= 1, r >>= 1) {
        if(l & 1)
            apply(l++, val);
        if(r + 1 & 1)
            apply(r--, val);
    }
    fixup(l0);
    fixup(r0);
}
     
lint query(int l, int r) {
    if(l > r)
      return -inf;
    lint ret = -inf;
    l += m;
    r += m;
    push(l);
    push(r);
    for(; l <= r; l >>= 1, r >>= 1) {
        if(l & 1)
            ret = max(ret, t[l++]);
        if(r + 1 & 1)
            ret = max(ret, t[r--]);
    }
    return ret;
}
     
     
void solve(int u) {
    vis[u] = true;
    if(adj[u].size() <= 1) {
        s.erase({val[u], tin[u]});
        return;
    }
    while(true) {
        int q = query(tin[u], tout[u]);
        auto it = s.lower_bound({query(tin[u], tout[u]), tin[u]});
        if(it == s.end())
            return;
        int mx = b[it->second];
        if(u == mx) {
            s.erase(it);
            for(int v : adj[u]) {
                if(vis[v] || p[u] == v)
                    continue;
                ans += val[u] + query(tin[v], tout[v]);
                solve(v);
            }
            return;
        }
        else {
            lint other = max(query(tin[u], tin[mx] - 1), query(tout[mx] + 1, tout[u]));
            ans += other + val[mx];
            solve(mx);
            update(tin[mx], tout[mx], 0);
        }
    }
    
}
     
     
signed main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    cin >> n;
    for(int i = 1; i <= n; i++)
        cin >> val[i];
    if(n == 1) {
    	cout << 0 << endl;
    	return 0;
    }
    if(n == 2) {
    	cout << val[1] + val[2] << endl;
    	return 0;
    }
    for(int i = 1, u, v; i < n; i++) {
        cin >> u >> v;
        adj[u].push_back(v);
        adj[v].push_back(u);
    }
    int root = -1;
    for(int i = 1; i <= n; i++)
        if(adj[i].size() > 1) {
            root = i;
            break;
        }
    dfs(root);
    build();
    solve(root);
    cout << ans << endl;
}

Compilation message (stderr)

sjekira.cpp: In function 'void update(int, int, lint)':
sjekira.cpp:75:14: warning: suggest parentheses around '+' in operand of '&' [-Wparentheses]
   75 |         if(r + 1 & 1)
      |            ~~^~~
sjekira.cpp: In function 'lint query(int, int)':
sjekira.cpp:93:14: warning: suggest parentheses around '+' in operand of '&' [-Wparentheses]
   93 |         if(r + 1 & 1)
      |            ~~^~~
sjekira.cpp: In function 'void solve(int)':
sjekira.cpp:107:13: warning: unused variable 'q' [-Wunused-variable]
  107 |         int q = query(tin[u], tout[u]);
      |             ^

• Subtask 1: 10 / 10
• Subtask 2: 0 / 10
• Subtask 3: 30 / 30
• Subtask 4: 0 / 60