algorithm/offlineonline.cpp

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• Last update: 2020-10-27 12:43:10+09:00
• Link: https://qiita.com/tmaehara/items/0687af2cfb807cde7860

Verified with

• test/aoj/3086.test.cpp
• test/yukicoder/1948.test.cpp
• test/yukicoder/1950.test.cpp
• test/yukicoder/2113.test.cpp

Code

#ifndef call_from_test
#include <bits/stdc++.h>
using namespace std;
#endif

// https://qiita.com/tmaehara/items/0687af2cfb807cde7860
//BEGIN CUT HERE
namespace OfflineOnline{
  vector<int> used;

  template<typename T>
  void update(vector<T> &dp,int k,T val){
    if(!used[k]) dp[k]=val;
    dp[k]=min(dp[k],val);
    used[k]=1;
  }

  // [l, r), [a, b]
  template<typename T,typename F>
  void induce(int l,int r,int a,int b,vector<T> &dp,F dist){
    if(l==r) return;
    int m=(l+r)>>1;
    assert(m<a);
    int idx=a;
    T res=dist(m,idx)+dp[idx];
    for(int i=a;i<=b;i++){
      T tmp=dist(m,i)+dp[i];
      if(tmp<res) res=tmp,idx=i;
    }
    update(dp,m,res);
    induce(l,m+0,a,idx,dp,dist);
    induce(m+1,r,idx,b,dp,dist);
  }

  template<typename T,typename F>
  void solve(int l,int r,vector<T> &dp,F dist){
    if(l+1==r) return update(dp,l,dist(l,r)+dp[r]);
    int m=(l+r)>>1;
    solve(m,r,dp,dist);
    induce(l,m,m,r,dp,dist);
    solve(l,m,dp,dist);
  }

  // dp[i] = min_{i<j} dist(i,j) + dp[j]
  template<typename T,typename F>
  T solve(int n,F dist){
    vector<T> dp(n+1,0);
    used.assign(n+1,0);
    used[n]=1;
    solve(0,n,dp,dist);
    return dp[0];
  }
};
//END CUT HERE
#ifndef call_from_test
//INSERT ABOVE HERE
signed main(){
  return 0;
}
#endif

#line 1 "algorithm/offlineonline.cpp"

#include <bits/stdc++.h>
using namespace std;
#endif

// https://qiita.com/tmaehara/items/0687af2cfb807cde7860
//BEGIN CUT HERE
namespace OfflineOnline{
  vector<int> used;

  template<typename T>
  void update(vector<T> &dp,int k,T val){
    if(!used[k]) dp[k]=val;
    dp[k]=min(dp[k],val);
    used[k]=1;
  }

  // [l, r), [a, b]
  template<typename T,typename F>
  void induce(int l,int r,int a,int b,vector<T> &dp,F dist){
    if(l==r) return;
    int m=(l+r)>>1;
    assert(m<a);
    int idx=a;
    T res=dist(m,idx)+dp[idx];
    for(int i=a;i<=b;i++){
      T tmp=dist(m,i)+dp[i];
      if(tmp<res) res=tmp,idx=i;
    }
    update(dp,m,res);
    induce(l,m+0,a,idx,dp,dist);
    induce(m+1,r,idx,b,dp,dist);
  }

  template<typename T,typename F>
  void solve(int l,int r,vector<T> &dp,F dist){
    if(l+1==r) return update(dp,l,dist(l,r)+dp[r]);
    int m=(l+r)>>1;
    solve(m,r,dp,dist);
    induce(l,m,m,r,dp,dist);
    solve(l,m,dp,dist);
  }

  // dp[i] = min_{i<j} dist(i,j) + dp[j]
  template<typename T,typename F>
  T solve(int n,F dist){
    vector<T> dp(n+1,0);
    used.assign(n+1,0);
    used[n]=1;
    solve(0,n,dp,dist);
    return dp[0];
  }
};
//END CUT HERE
#ifndef call_from_test
//INSERT ABOVE HERE
signed main(){
  return 0;
}
#endif

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