Submission #985314

#	Time	Username	Problem	Language	Result	Execution time	Memory
985314		yeediot	Election Campaign (JOI15_election_campaign)	C++17	100 / 100	110 ms	27912 KiB

election_campaign

#include<bits/stdc++.h>
using namespace std;
#define F first
#define S second
#define all(x) x.begin(),x.end()
#define pii pair<int,int>
#define pb push_back
#define sz(x) (int)(x.size())
#define chmin(x,y) x=min(x,y)
#define chmax(x,y) x=max(x,y)
#define vi vector<int>
#define vp vector<pii>
#define vvi vector<vi>
#define ykh mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count())
#define __lg(x) 63-__builtin_clzll(x)
#define pow2(x) (1LL<<x)
void __print(int x) {cerr << x;}
void __print(float x) {cerr << x;}
void __print(double x) {cerr << x;}
void __print(long double x) {cerr << x;}
void __print(char x) {cerr << '\'' << x << '\'';}
void __print(const char *x) {cerr << '\"' << x << '\"';}
void __print(const string &x) {cerr << '\"' << x << '\"';}
void __print(bool x) {cerr << (x ? "true" : "false");}

template<typename T, typename V>
void __print(const pair<T, V> &x) {cerr << '{'; __print(x.first); cerr << ','; __print(x.second); cerr << '}';}
template<typename T>
void __print(const T &x) {int f = 0; cerr << '{'; for (auto &i: x) cerr << (f++ ? "," : ""), __print(i); cerr << "}";}
void _print() {cerr << "]\n";}
template <typename T, typename... V>
void _print(T t, V... v) {__print(t); if (sizeof...(v)) cerr << ", "; _print(v...);}
#ifdef local
void setio(){freopen("/Users/iantsai/Library/Mobile Documents/com~apple~CloudDocs/cpp/Empty.md","r",stdin);}
#define debug(x...) cerr << "[" << #x << "] = ["; _print(x)
#else
void setio(){}
#define debug(x...)
#endif
void setIO(string s) {
    freopen((s + ".in").c_str(), "r", stdin);
    freopen((s + ".out").c_str(), "w", stdout);
}
struct line{
    int a,b;
    int operator()(const int x)const{
        return a*x+b;
    }
};
bool check(line l1,line l2,line l3){
    return (l3.b-l2.b)*(l1.a-l2.a)<=(l2.b-l1.b)*(l2.a-l3.a);
}
const int mxn=1e5+5;
int n, q, jump[20][mxn], in[mxn], out[mxn], timer, dep[mxn], dp[mxn];
vector<int>adj[mxn];
vector<tuple<int,int,int>>as[mxn];
struct BIT{
    int bit[mxn];
    void init(){
        for(int i=0;i<mxn;i++){
            bit[i]=0;
        }
    }
    void modify(int p,int v){
        for(;p<mxn;p+=p&-p){
            bit[p]+=v;
        }
    }
    void modify(int l,int r,int v){
        modify(l,v);
        modify(r+1,-v);
    }
    int query(int p){
        int res=0;
        for(;p;p-=p&-p){
            res+=bit[p];
        }
        return res;
    }
}bt;
void dfs(int v,int pa){
    in[v]=++timer;
    jump[0][v]=pa;
    dep[v]=dep[pa]+1;
    for(auto u:adj[v]){
        if(u==pa)
            continue;
        dfs(u,v);
    }
    out[v]=timer;
}
int lca(int a,int b){
    if(dep[a]<dep[b])swap(a,b);
    int dif=dep[a]-dep[b];
    for(int i=0;i<20;i++){
        if(dif>>i&1)
            a=jump[i][a];
    }
    if(a==b)
        return a;
    for(int i=19;i>=0;i--){
        if(jump[i][a]!=jump[i][b]){
            a=jump[i][a];
            b=jump[i][b];
        }
    }
    return jump[0][a];
}
void calc(int v,int pa){
    int sum=0;
    for(auto u:adj[v]){
        if(u==pa)
            continue;
        calc(u,v);
        sum+=dp[u];
    }
    dp[v]=sum;
    for(auto [a,b,c]:as[v]){
        dp[v]=max(dp[v],sum+c+bt.query(in[a])+bt.query(in[b]));
    }
    bt.modify(in[v],out[v],sum-dp[v]);
}
signed main(){
    setio();
    ios::sync_with_stdio(0);
    cin.tie(0);cout.tie(0);
    cin>>n;
    for(int i=1;i<n;i++){
        int a,b;
        cin>>a>>b;
        adj[a].pb(b);
        adj[b].pb(a);
    }
    bt.init();
    dfs(1,1);
    for(int i=1;i<20;i++){
        for(int j=1;j<=n;j++){
            jump[i][j]=jump[i-1][jump[i-1][j]];
        }
    }
    cin>>q;
    for(int i=0;i<q;i++){
        int a,b,c;
        cin>>a>>b>>c;
        as[lca(a,b)].pb({a,b,c});
    }
    calc(1,1);
    cout<<dp[1]<<'\n';
}
 /*
 input:
 
 */















 

Compilation message (stderr)

election_campaign.cpp: In function 'void setIO(std::string)':
election_campaign.cpp:41:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   41 |     freopen((s + ".in").c_str(), "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
election_campaign.cpp:42:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   42 |     freopen((s + ".out").c_str(), "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