Submission #94987

#	Time	Username	Problem	Language	Result	Execution time	Memory
94987		bogdan10bos	Election Campaign (JOI15_election_campaign)	C++14	100 / 100	271 ms	38132 KiB

election_campaign

#include <bits/stdc++.h>

using namespace std;

//#define FILE_IO

typedef long long LL;

const int NMAX = 1e5;
const int LG = 17;

typedef pair<int, int> pii;

LL dp[NMAX + 5], dp0[NMAX + 5];
int N, M;
int h[NMAX + 5], f[NMAX + 5];
int I, itv[NMAX + 5][2], lg2[2 * NMAX + 5], rmq[LG + 1][2 * NMAX + 5];
int cost[NMAX + 5];
pii path[NMAX + 5];
vector<int> edg[NMAX + 5], pth[NMAX + 5];

class BinaryIndexedTree
{
public:
    int N;
    LL aib[2 * NMAX + 5];

    void U(int pos, int val)
    {
        for(; pos <= N; pos += (pos & (-pos)))
            aib[pos] += val;
    }

    LL Q(int pos)
    {
        LL ans = 0;
        for(; pos > 0; pos -= (pos & (-pos)))
            ans += aib[pos];
        return ans;
    }
}sumdp, sumdp0;

void DFS(int nod, int fth)
{
    f[nod] = fth;
    h[nod] = h[fth] + 1;
    itv[nod][0] = ++I;
    rmq[0][I] = nod;

    for(auto nxt: edg[nod])
        if(nxt != fth)
            DFS(nxt, nod);

    itv[nod][1] = ++I;
    rmq[0][I] = nod;
}

int minh(int a, int b)  { if(h[a] < h[b]) return a; return b; }
int LCA(int a, int b)
{
    int pa = itv[a][0], pb = itv[b][0];
    if(pa > pb) swap(a, b), swap(pa, pb);
    if(itv[a][0] <= itv[b][0] && itv[b][1] <= itv[a][1])    return a;
    int pw = lg2[pb - pa + 1];
    int nod = minh(rmq[pw][pa], rmq[pw][pb - (1 << pw) + 1]);
    return f[nod];
}

void solve(int nod)
{
    for(auto nxt: edg[nod])
        if(nxt != f[nod])
        {
            solve(nxt);
            dp0[nod] += dp[nxt];
        }
    sumdp0.U(itv[nod][0], dp0[nod]);
    sumdp0.U(itv[nod][1], -dp0[nod]);

    dp[nod] = dp0[nod];
    for(auto id: pth[nod])
    {
        int x = path[id].first, y = path[id].second;
        LL val = cost[id] + dp0[nod];
        val += sumdp0.Q(itv[x][0]) - sumdp0.Q(itv[nod][0]);
        val += sumdp0.Q(itv[y][0]) - sumdp0.Q(itv[nod][0]);
        val -= sumdp.Q(itv[x][0]) - sumdp.Q(itv[nod][0]);
        val -= sumdp.Q(itv[y][0]) - sumdp.Q(itv[nod][0]);
        dp[nod] = max(dp[nod], val);
    }

    sumdp.U(itv[nod][0], dp[nod]);
    sumdp.U(itv[nod][1], -dp[nod]);
}

int main()
{
    #ifdef FILE_IO
    freopen("1.in", "r", stdin);
    //freopen("1.out", "w", stdout);
    #endif

    scanf("%d", &N);
    for(int i = 1; i < N; i++)
    {
        int x, y;
        scanf("%d%d", &x, &y);
        edg[x].push_back(y);
        edg[y].push_back(x);
    }

    DFS(1, 0);
    for(int i = 2; i <= I; i++) lg2[i] = lg2[i >> 1] + 1;
    for(int i = 1; (1 << i) <= I; i++)
        for(int j = 1; j + (1 << i) - 1 <= I; j++)
            rmq[i][j] = minh(rmq[i - 1][j], rmq[i - 1][j + (1 << (i - 1))]);

    scanf("%d", &M);
    for(int i = 1; i <= M; i++)
    {
        int a, b, c;
        scanf("%d%d%d", &a, &b, &c);
        path[i] = {a, b};
        cost[i] = c;
        pth[LCA(a, b)].push_back(i);
    }

    sumdp.N = I, sumdp0.N = I;
    solve(1);
    printf("%d\n", dp[1]);

    return 0;
}

Compilation message (stderr)

election_campaign.cpp: In function 'int main()':
election_campaign.cpp:130:25: warning: format '%d' expects argument of type 'int', but argument 2 has type 'LL {aka long long int}' [-Wformat=]
     printf("%d\n", dp[1]);
                    ~~~~~^
election_campaign.cpp:103:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d", &N);
     ~~~~~^~~~~~~~~~
election_campaign.cpp:107:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d%d", &x, &y);
         ~~~~~^~~~~~~~~~~~~~~~
election_campaign.cpp:118:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d", &M);
     ~~~~~^~~~~~~~~~
election_campaign.cpp:122:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d%d%d", &a, &b, &c);
         ~~~~~^~~~~~~~~~~~~~~~~~~~~~

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