Submission #1290225

#	Time	Username	Problem	Language	Result	Execution time	Memory
1290225		vuquangsang	Construction of Highway (JOI18_construction)	C++20	7 / 100	2095 ms	1016 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


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];
void inp()
{
    cin >> n;
    FOR(i, 1, n) cin >> a[i];
    FOR(i, 1, n - 1) {
        int x, y; cin >> x >> y;
        adj[x].push_back(y);
        adj[y].push_back(x);
        E[i] = {x, y};
    }
}


namespace subtask_1
{

    int h[N], par[N];

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

    int calc(int x)
    {
        int ans = 0;
        int cur = x;
        while(cur > 0) {
            if(a[cur] > a[x]) ans++;
            cur = par[cur];
        }
        return ans;
    }
    void slv()
    {
        dfs(1, 1);
        FOR(i, 1, n - 1) {
            int x = E[i].first, y = E[i].second;

            int cur = x;
            int ans = 0;
            while(cur > 0) {
                ans += calc(cur);
                cur = par[cur];
            }
            cur = x;
            while(cur > 0) {
                a[cur] = a[y];
                cur = par[cur];
            }
            cout << ans << el;
        }
    }
}

namespace subtask_2
{

    int sz[N], h[N], par[N];

    void dfs(int u, int p)
    {
        sz[u] = 1;
        for(int v : adj[u]) if(v != p) {
            h[v] = h[u] + 1;
            par[v] = u;
            dfs(v, u);
            sz[u] += sz[v];
        }
    }
    int head[N], chainID[N], mtc = 1, time = 0, pos[N], euler[N];

    void hld(int u, int p)
    {
        if(!head[mtc]) {
            head[mtc] = u;
        }
        chainID[u] = mtc;

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

        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], lz[4 * N];

    int calc(int x)
    {
        int ans = 0;
        while(chainID[x] != chainID[1]) {

            }
    }
    void slv()
    {
        dfs(1, 1);
        hld(1, 1);

        FOR(i, 1, n - 1) {
            int x = E[i].first, y = E[i].second;

            int ans = 0;
            int cur = x;
            while(cur > 0) {
                ans += calc(cur);
                cur = par[cur];
            }
        }
    }
}

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);
    }

    bool qs = 0;

    int T = 1;
    if(qs) cin >> T;
    while(T--) {
        inp();
        subtask_1::slv();
    }

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


}

Compilation message (stderr)

construction.cpp: In function 'int subtask_2::calc(int)':
construction.cpp:130:5: warning: no return statement in function returning non-void [-Wreturn-type]
  130 |     }
      |     ^
construction.cpp: At global scope:
construction.cpp:149:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
  149 | main()
      | ^~~~
construction.cpp: In function 'int main()':
construction.cpp:155:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  155 |         freopen(__Azul__".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~
construction.cpp:156:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  156 |         freopen(__Azul__".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 7 / 7
• Subtask 2: 0 / 9
• Subtask 3: 0 / 84