Submission #1284738

#	Time	Username	Problem	Language	Result	Execution time	Memory
1284738		icebear	Construction of Highway (JOI18_construction)	C++20	16 / 100	78 ms	872 KiB

construction

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

typedef long long ll;
typedef pair<int, int> ii;
typedef pair<int, ii> iii;

template<class T>
    bool minimize(T &a, const T &b) {
        if (a > b) return a = b, true;
        return false;
    }

template<class T>
    bool maximize(T &a, const T &b) {
        if (a < b) return a = b, true;
        return false;
    }

#define FOR(i,a,b) for(int i=(a); i<=(b); ++i)
#define FORR(i,a,b) for(int i=(a); i>=(b); --i)
#define REP(i, n) for(int i=0; i<(n); ++i)
#define RED(i, n) for(int i=(n)-1; i>=0; --i)
#define MASK(i) (1LL << (i))
#define BIT(S, i) (((S) >> (i)) & 1)
#define mp make_pair
#define pb push_back
#define fi first
#define se second
#define all(x) x.begin(), x.end()
#define task "icebear"
/*END OF TEMPLATE. ICEBEAR AND THE CAT WILL WIN VOI26 */

const int MOD = 1e9 + 7;
const int inf = 1e9 + 27092008;
const ll INF = 1e18 + 27092008;
const int N = 4000 + 5;
int n, C[N];
vector<int> G[N], compress;
ii edge[N];
int par[N], ft[N];

void update(int x, int v) {
    for(; x <= n; x += x & -x) ft[x] += v;
}

int get(int x) {
    int ans = 0;
    for(; x; x -= x & -x) ans += ft[x];
    return ans;
}

void dfs(int u) {
    for(int v : G[u]) if (v != par[u]) {
        par[v] = u;
        dfs(v);
    }
}

void init(void) {
    cin >> n;
    FOR(i, 1, n) cin >> C[i], compress.pb(C[i]);
    sort(all(compress));
    compress.resize(unique(all(compress)) - compress.begin());
    FOR(i, 1, n) C[i] = upper_bound(all(compress), C[i]) - compress.begin();
    FOR(i, 2, n) {
        int u, v;
        cin >> u >> v;
        G[u].pb(v);
        G[v].pb(u);
        edge[i] = mp(u, v);
    }
}

void process(void) {
    dfs(1);
    FOR(i, 2, n) {
        memset(ft, 0, sizeof ft);
        int u = edge[i].fi;
        int ans = 0;
        while(u > 0) {
            ans += get(C[u] - 1);
            update(C[u], +1);
            C[u] = C[edge[i].se];
            u = par[u];
        }
        cout << ans << '\n';
    }
}

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    if (fopen(task".inp", "r")) {
        freopen(task".inp", "r", stdin);
        freopen(task".out", "w", stdout);
    }
    int tc = 1;
//    cin >> tc;
    while(tc--) {
        init();
        process();
    }
    return 0;
}

Compilation message (stderr)

construction.cpp: In function 'int main()':
construction.cpp:96:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   96 |         freopen(task".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
construction.cpp:97:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   97 |         freopen(task".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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