Submission #1290281

#	Time	Username	Problem	Language	Result	Execution time	Memory
1290281		vuquangsang	Construction of Highway (JOI18_construction)	C++20	100 / 100	330 ms	19376 KiB

construction

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

#define     el "\n"
#define     FOR(i,a,b) for(int i = (a), _b = (b); i <= _b; i++)
#define     FORD(i,a,b) for(int i = (a), _b = (b); i >= _b; i--)
#define     pb push_back
#define     fi first
#define     se second
#define     all(x) x.begin(),x.end()
#define     lg(x) __lg(x)
#define     alla(a,n) a+1,a+n+1
#define     ll long long
#define     pii pair<int, int>


template <class T> bool maxi(T &x, T y) { if(x < y) { x = y ; return true ;} return false;}
template <class T> bool mini(T &x, T y) { if(x > y) { x = y ; return true ;} return false;}

const int N = 1e5 + 2;

int n, a[N];
vector<int> adj[N];
pair<int, int> E[N];

int sz[N], par[N];

void dfs(int u, int p)
{
    sz[u] = 1;
    for(int v : adj[u]) if(v != p) {
        par[v] = u;
        dfs(v, u);
        sz[u] += sz[v];
    }
}

int head[N], chainID[N], euler[N], pos[N], timer = 0, mtc = 1;
void hld(int u, int p)
{
    if(!head[mtc]) {
        head[mtc] = u;
    }
    chainID[u] = mtc;

    euler[++timer] = u;
    pos[u] = timer;

    int ma = 0;
    for(int v : adj[u]) if(v != p) {
        if(!ma || sz[v] > sz[ma]) ma = v;
    }
    if(ma) hld(ma, u);
    for(int v : adj[u]) if(v != p && v != ma) {
        mtc++;
        hld(v, u);
    }
}

int st[4 * N], bit[N];

void upd(int x, int v)
{
    for(; x <= n; x += x & -x) bit[x] += v;
}
int get(int x)
{
    int ans = 0;
    for(; x >= 1; x -= x & -x) ans += bit[x];
    return ans;
}

void down(int id)
{
    if(st[id] == -1) return;
    st[id << 1] = st[id << 1 | 1] = st[id];
}
void upd(int id, int l, int r, int u, int v, int val)
{
    if(r < u || v < l) return;
    if(u <= l && r <= v) {
        st[id] = val;
        return;
    }
    int mid = (r + l) >> 1;
    down(id);
    upd(id << 1, l, mid, u, v, val);
    upd(id << 1 | 1, mid + 1, r, u, v, val);
    if(st[id << 1] == st[id << 1 | 1]) st[id] = st[id << 1];
    else st[id] = -1;
}

stack<pair<int, int>> memo;
int get(int id, int l, int r, int u, int v)
{
    if(r < u || v < l) return 0;
    if(u <= l && r <= v && st[id] != -1) {
        int res = (r - l + 1) * get(st[id] - 1);
        upd(st[id], r - l + 1);
        memo.push({st[id], r - l + 1});
        return res;
    }
    int mid = (r + l) >> 1;
    down(id);
    return get(id << 1 | 1, mid + 1, r, u, v) + get(id << 1, l, mid, u, v);
}
int calc(int u)
{
    upd(1, 1, n, pos[u], pos[u], a[u]);
    int val = a[u];

    u = par[u];
    int ans = 0;
    while(u > 0) {
        ans += get(1, 1, n, pos[head[chainID[u]]], pos[u]);
        upd(1, 1, n, pos[head[chainID[u]]], pos[u], val);
        u = par[head[chainID[u]]];
    }
    while(!memo.empty()) {
        int pos = memo.top().first;
        int val = memo.top().second;
        memo.pop();

        upd(pos, -val);
    }
    return ans;
}
void solve()
{
    cin >> n;
    vector<int> V;
    FOR(i, 1, n) cin >> a[i], V.push_back(a[i]);
    sort(all(V));
    V.resize(unique(all(V)) - V.begin());
    FOR(i, 1, n) {
        a[i] = lower_bound(all(V), a[i]) - V.begin() + 1;
    }
    FOR(i, 1, n - 1) {
        int x, y; cin >> x >> y;
        E[i] = {x, y};
        adj[x].push_back(y);
        adj[y].push_back(x);
    }

    dfs(1, 1);
    hld(1, 1);

    memset(st, -1, sizeof st);

    calc(1);
    FOR(i, 1, n - 1) {
        cout << calc(E[i].second) << el;

    }
}

main()
{
    ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);

    #define __Azul__ "JOI18_construction"
    if(fopen(__Azul__".inp", "r")) {
        freopen(__Azul__".inp", "r", stdin);
        freopen(__Azul__".out", "w", stdout);
    }

    solve();

    cerr << "\nTime" << 0.001 * clock() << "s "; return 0;


}

Compilation message (stderr)

construction.cpp:157:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
  157 | main()
      | ^~~~
construction.cpp: In function 'int main()':
construction.cpp:163:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  163 |         freopen(__Azul__".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~
construction.cpp:164:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  164 |         freopen(__Azul__".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 7 / 7
• Subtask 2: 9 / 9
• Subtask 3: 84 / 84