Submission #486769

#	Time	Username	Problem	Language	Result	Execution time	Memory
486769		Nimbostratus	Sjekira (COCI20_sjekira)	C++17	110 / 110	185 ms	25156 KiB

sjekira

#include "bits/stdc++.h"
#define endl '\n'
#define int long long
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];
int m, h;
int tin[maxn], tout[maxn], b[2 * maxn], p[maxn];
pll t[4 * maxn];
int 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++;
}

void build() {
    h = 8 * sizeof(int) - __builtin_clz(m);
    for(int i = 0; i < m; i++) {
    	t[m + i].first = val[b[i]];
    	t[m + i].second = 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].first *= 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]);
        t[u].first *= lz[u];
    }
}
     
void push(int u) {
    for(int k = h; k > 0; k--) {
        int s = u >> k;
        if(!s)
            continue;        
        apply(s << 1, lz[s]);
        apply(s << 1 | 1, lz[s]);
        lz[s] = 1;
    }
}
     
void update(int l, int r, lint k) {
    l += m;
    r += m;
    int l0 = l, r0 = r;
    for(; l <= r; l >>= 1, r >>= 1) {
        if(l & 1)
            apply(l++, k);
        if(r + 1 & 1)
            apply(r--, k);
    }
    fixup(l0);
    fixup(r0);
}
     
pll query(int l, int r) {
    pll ret = {-inf, 0};
    if(l > r)
    	return ret;
    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) {
    	update(tin[u], tout[u], 0);
        return;
    }
    while(true) {
    	lint x, mx;
        tie(x, mx) = query(tin[u], tout[u]);
        if(u == mx) {
            for(int v : adj[u]) {
                if(vis[v] || p[u] == v)
                    continue;
                ans += x + query(tin[v], tout[v]).first;
                solve(v);
                update(tin[v], tout[v], 0);
            }
            update(tin[u], tout[u], 0);
            return;
        }
        else {
        	lint q1 = query(tin[u], tin[mx] - 1).first;
        	lint q2 = query(tout[mx] + 1, tout[u]).first;
            lint comp2 = max(q1, q2);
            ans += comp2 + x;
            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(long long int, long long int, lint)':
sjekira.cpp:79:14: warning: suggest parentheses around '+' in operand of '&' [-Wparentheses]
   79 |         if(r + 1 & 1)
      |            ~~^~~
sjekira.cpp: In function 'pll query(long long int, long long int)':
sjekira.cpp:97:14: warning: suggest parentheses around '+' in operand of '&' [-Wparentheses]
   97 |         if(r + 1 & 1)
      |            ~~^~~

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