Submission #1282785

#	Time	Username	Problem	Language	Result	Execution time	Memory
1282785		icebear	Election Campaign (JOI15_election_campaign)	C++20	100 / 100	140 ms	57012 KiB

election_campaign

// ~~ 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 = 2e5 + 5;
int n, q, P[N][20], h[N];
vector<int> G[N];
vector<iii> sche[N];
ll f[N], sum[N][20], tmpINF;

void dfs(int u, int par) {
    for(int v : G[u]) if (v != par) {
        P[v][0] = u;
        h[v] = h[u] + 1;
        dfs(v, u);
    }
}

int jump(int u, int k) {
    REP(j, 20) if (BIT(k, j))
        u = P[u][j];
    return u;
}

int LCA(int u, int v) {
    if (h[u] < h[v]) swap(u, v);
    u = jump(u, h[u] - h[v]);
    if (u == v) return u;
    RED(j, 20) if (P[u][j] != P[v][j]) {
        u = P[u][j];
        v = P[v][j];
    }
    return P[u][0];
}

ll sumPath(int u, int j) {
    if (sum[u][j] != tmpINF) return sum[u][j];
    return sum[u][j] = sumPath(u, j - 1) + sumPath(P[u][j - 1], j - 1);
}

ll splitTree(int u, int acs) {
    if (u == acs) return 0;
    ll res = 0;
    int dist = h[u] - h[acs] - 1;
    RED(j, 20) if (BIT(dist, j)) {
        res += sumPath(u, j);
        u = P[u][j];
    }
    res += sum[u][0];
    return res;
}

void calc(int u, int par) {
    sum[u][0] = 0;
    for(int v : G[u]) if (v != par) {
        calc(v, u);
        f[u] += f[v];
        sum[u][0] += f[v];
    }
    ll add = 0;
    for(auto &x : sche[u]) {
        int C = x.fi;
        int A, B; tie(A, B) = x.se;
        maximize(add, splitTree(A, u) + splitTree(B, u) + C);
    }
    f[u] += add;
    sum[u][0] -= f[u];
}

void init(void) {
    cin >> n;
    FOR(i, 2, n) {
        int u, v;
        cin >> u >> v;
        G[u].pb(v);
        G[v].pb(u);
    }
    dfs(1, -1);
    FOR(j, 1, 19) FOR(i, 1, n) P[i][j] = P[P[i][j - 1]][j - 1];
    cin >> q;
    FOR(i, 1, q) {
        int a, b, c;
        cin >> a >> b >> c;
        sche[LCA(a, b)].pb(mp(c, mp(a, b)));
    }
}

void process(void) {
    memset(sum, -0x3f, sizeof sum);
    tmpINF = sum[0][0];
    calc(1, -1);
    cout << f[1] << '\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)

election_campaign.cpp: In function 'int main()':
election_campaign.cpp:132:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  132 |         freopen(task".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
election_campaign.cpp:133:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  133 |         freopen(task".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 5 / 5
• Subtask 3: 5 / 5
• Subtask 4: 30 / 30
• Subtask 5: 10 / 10
• Subtask 6: 40 / 40