Submission #128506

#	Time	Username	Problem	Language	Result	Execution time	Memory
128506		mirbek01	Election Campaign (JOI15_election_campaign)	C++11	100 / 100	367 ms	31796 KiB

election_campaign

# include <bits/stdc++.h>

using namespace std;

const int N = 1e5 + 2;

int n, m, a[N], b[N], c[N], dp[N], sv[N];
int up[17][N], tin[N], tout[N], timer, ver[N];
int t[N * 4], add[N * 4];
vector <int> g[N], qe[N];

void dfs(int v, int pr){
      tin[v] = ++ timer;
      ver[timer] = v;
      up[0][v] = pr;
      for(int i = 1; i <= 16; i ++)
            up[i][v] = up[i - 1][up[i - 1][v]];
      for(int to : g[v]){
            if(to == pr)
                  continue;
            dfs(to, v);
      }
      tout[v] = timer;
}

bool upper(int a, int b){
      return tin[a] <= tin[b] && tout[a] >= tout[b];
}

int lca(int a, int b){
      if(upper(a, b))
            return a;
      if(upper(b, a))
            return b;
      for(int i = 16; i >= 0; i --){
            if(!upper(up[i][a], b))
                  a = up[i][a];
      }
      return up[0][a];
}

void push(int v, int tl, int tr){
      t[v] += (tr - tl + 1) * add[v];
      if(tl != tr){
            add[v << 1] += add[v];
            add[v << 1 | 1] += add[v];
      }
      add[v] = 0;
}

void upd(int l, int r, int val, int v = 1, int tl = 1, int tr = n){
      push(v, tl, tr);
      if(l > tr || tl > r)
            return ;
      if(l <= tl && tr <= r){
            add[v] += val;
            push(v, tl, tr);
            return ;
      }
      int tm = (tl + tr) >> 1;
      upd(l, r, val, v << 1, tl, tm);
      upd(l, r, val, v << 1 | 1, tm + 1, tr);
      t[v] = t[v << 1] + t[v << 1 | 1];
}

int get(int pos, int v = 1, int tl = 1, int tr = n){
      push(v, tl, tr);
      if(tl == tr)
            return t[v];
      int tm = (tl + tr) >> 1;
      if(pos <= tm)
            return get(pos, v << 1, tl, tm);
      return get(pos, v << 1 | 1, tm + 1, tr);
}

void calc(int v, int pr){
      for(int to : g[v]){
            if(to == pr)
                  continue;
            calc(to, v);
            sv[v] += dp[to];
      }

      for(int to : g[v]){
            if(to == pr)
                  continue;
            upd(tin[to], tout[to], sv[v] - dp[to]);
      }

      dp[v] = sv[v];

      for(int i : qe[v]){
            int ret = sv[ a[i] ] + sv[ b[i] ] - sv[v] + c[i];
            ret += get(tin[ a[i] ]);
            ret += get(tin[ b[i] ]);
            dp[v] = max(dp[v], ret);
      }
}

int main(){
      scanf("%d", &n);

      for(int i = 1; i < n; i ++){
            int u, v;
            scanf("%d %d", &u, &v);
            g[u].push_back(v);
            g[v].push_back(u);
      }

      dfs(1, 1);

      scanf("%d", &m);

      for(int i = 1; i <= m; i ++){
            scanf("%d %d %d", a+i, b+i, c+i);
            qe[ lca(a[i], b[i]) ].push_back(i);
      }

      calc(1, 1);

      cout << dp[1] << endl;
}

Compilation message (stderr)

election_campaign.cpp: In function 'int main()':
election_campaign.cpp:101:12: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
       scanf("%d", &n);
       ~~~~~^~~~~~~~~~
election_campaign.cpp:105:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
             scanf("%d %d", &u, &v);
             ~~~~~^~~~~~~~~~~~~~~~~
election_campaign.cpp:112:12: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
       scanf("%d", &m);
       ~~~~~^~~~~~~~~~
election_campaign.cpp:115:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
             scanf("%d %d %d", a+i, b+i, c+i);
             ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

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