Submission #1007551

#	Time	Username	Problem	Language	Result	Execution time	Memory
1007551		huutuan	Salesman (IOI09_salesman)	C++14	100 / 100	311 ms	28096 KiB

salesman

#include <bits/stdc++.h>

using namespace std;

const int N=5e5+10;
const int inf=2e9;

struct SegmentTree{
   int n;
   vector<int> t;
   void init(int _n){
      n=_n;
      t.assign(4*n+1, -inf);
   }
   void update(int k, int l, int r, int pos, int val){
      if (l==r){
         t[k]=val;
         return;
      }
      int mid=(l+r)>>1;
      if (pos<=mid) update(k<<1, l, mid, pos, val);
      else update(k<<1|1, mid+1, r, pos, val);
      t[k]=max(t[k<<1], t[k<<1|1]);
   }
   int get(int k, int l, int r, int L, int R){
      if (r<L || R<l) return -inf;
      if (L<=l && r<=R) return t[k];
      int mid=(l+r)>>1;
      return max(get(k<<1, l, mid, L, R), get(k<<1|1, mid+1, r, L, R));
   }
} st1, st2;

int n, s, f[N], f1[N], f2[N], val[N];
int u, d;
vector<pair<int, int>> vv;

void calc(int t, int l, int r){
   for (int ii=l; ii<=r; ++ii){
      int i=vv[ii].second;
      f1[i]=f2[i]=max(st1.get(1, 1, st1.n, 1, i)-d*i, st2.get(1, 1, st2.n, i, st2.n)+u*i);
   }
   f2[vv[l].second]+=val[vv[l].second];
   f1[vv[r].second]+=val[vv[r].second];
   for (int i=l+1; i<=r; ++i) f2[vv[i].second]=max(f2[vv[i].second], f2[vv[i-1].second]-d*(vv[i].second-vv[i-1].second))+val[vv[i].second];
   for (int i=r-1; i>=l; --i) f1[vv[i].second]=max(f1[vv[i].second], f1[vv[i+1].second]-u*(vv[i+1].second-vv[i].second))+val[vv[i].second];
   for (int ii=l; ii<=r; ++ii){
      int i=vv[ii].second;
      f[i]=max(f1[i], f2[i]);
      st1.update(1, 1, st1.n, i, f[i]+d*i);
      st2.update(1, 1, st2.n, i, f[i]-u*i);
   }
}

int32_t main(){
   ios_base::sync_with_stdio(false);
   cin.tie(nullptr);
   cin >> n >> u >> d >> s;
   for (int i=1; i<=n; ++i){
      int t, l, m; cin >> t >> l >> m;
      vv.emplace_back(t, l);
      val[l]=m;
   }
   vv.emplace_back(0, s);
   vv.emplace_back(500001, s);
   sort(vv.begin(), vv.end());
   st1.init(N); st2.init(N);
   for (int i=0; i<N; ++i) f[i]=-inf;
   f[s]=0;
   st1.update(1, 1, st1.n, s, f[s]+d*s);
   st2.update(1, 1, st2.n, s, f[s]-u*s);
   for (int i=1; i<(int)vv.size(); ++i){
      int j=i;
      while (j+1<(int)vv.size() && vv[j+1].first==vv[i].first) ++j;
      calc(vv[i].first, i, j);
      i=j;
   }
   cout << f[s] << '\n';
   return 0;
}

• Subtask 1: 100 / 100