Submission #362564

#	Time	Username	Problem	Language	Result	Execution time	Memory
362564		denkendoemeer	Election Campaign (JOI15_election_campaign)	C++14	100 / 100	370 ms	42900 KiB

election_campaign

#include<bits/stdc++.h>
#define ll long long
using namespace std;
ll n,u,s[100005],e[100005],dep[100005],t[25][100005],d[100005];
vector<ll>g[100005];
vector<tuple<ll,ll,ll>>v[100005];
struct ain
{
    ll aint[400005],lim;
    void init()
    {
        lim=1;
        while(lim<=n)
            lim=lim*2;
    }
    void update(ll a,ll b,ll nr)
    {
        a+=lim;
        b+=lim;
        while(a<=b)
        {
            if (a%2==1)
                aint[a++]+=nr;
            if (b%2==0)
                aint[b--]+=nr;
            a=a/2;
            b=b/2;
        }
    }
    ll query(ll poz)
    {
        ll ans=0;
        poz+=lim;
        while(poz){
            ans=ans+aint[poz];
            poz=poz/2;
        }
        return ans;
    }
}ai;
ll lca(ll x,ll y)
{
    if (dep[x]>dep[y])
        swap(x,y);
    ll i;
    for(i=20;i>=0;i--)
        if (dep[y]-dep[x]>=(1<<i))
            y=t[i][y];
    if (x==y)
        return x;
    for(i=20;i>=0;i--)
        if (t[i][x]!=t[i][y]){
            x=t[i][x];
            y=t[i][y];
        }
    return t[0][x];
}
void dfs(ll nod,ll ta)
{
    s[nod]=++u;
    dep[nod]=dep[ta]+1;
    t[0][nod]=ta;
    for(auto it:g[nod])
        if (it!=ta)
            dfs(it,nod);
    e[nod]=u;
}
void solve(ll nod,ll ta)
{
    ll ans=0;
    for(auto it:g[nod]){
        if (it==ta)
            continue;
        solve(it,nod);
        ans=ans+d[it];
    }
    d[nod]=ans;
    for(auto it:v[nod]){
        ll a,b,c;
        tie(a,b,c)=it;
        d[nod]=max(d[nod],ans+ai.query(s[a])+ai.query(s[b])+c);
    }
    ai.update(s[nod],e[nod],ans-d[nod]);
}
int main()
{
    //freopen(".in","r",stdin);
    //freopen(".out","w",stdout);
    ll i,x,y;
    scanf("%lld",&n);
    for(i=1;i<n;i++){
        scanf("%lld%lld",&x,&y);
        g[x].push_back(y);
        g[y].push_back(x);
    }
    dfs(1,0);
    ll j;
    for(i=1;i<20;i++)
        for(j=1;j<=n;j++)
            t[i][j]=t[i-1][t[i-1][j]];
    ll m;
    scanf("%lld",&m);
    for(i=1;i<=m;i++){
        ll z;
        scanf("%lld%lld%lld",&x,&y,&z);
        ll nod=lca(x,y);
        v[nod].push_back(make_tuple(x,y,z));
    }
    ai.init();
    solve(1,0);
    printf("%lld\n",d[1]);
return 0;
}

Compilation message (stderr)

election_campaign.cpp: In function 'int main()':
election_campaign.cpp:90:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   90 |     scanf("%lld",&n);
      |     ~~~~~^~~~~~~~~~~
election_campaign.cpp:92:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   92 |         scanf("%lld%lld",&x,&y);
      |         ~~~~~^~~~~~~~~~~~~~~~~~
election_campaign.cpp:102:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  102 |     scanf("%lld",&m);
      |     ~~~~~^~~~~~~~~~~
election_campaign.cpp:105:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  105 |         scanf("%lld%lld%lld",&x,&y,&z);
      |         ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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