Submission #100029

#	Time	Username	Problem	Language	Result	Execution time	Memory
100029		jamielim	Roller Coaster Railroad (IOI16_railroad)	C++14	34 / 100	129 ms	10752 KiB

railroad

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

long long adj[20][20];
long long memo[20][66000];

long long tsp(int x,int bm){
    if(memo[x][bm]!=-1)return memo[x][bm];
    if(bm==0)return memo[x][bm]=0;
    long long ans=1000000000000000010;
    int bm2=bm;
    while(bm2&(-bm2)){
        int y=__builtin_ctz(bm2);
        ans=min(ans,tsp(y,bm-(bm2&(-bm2)))+adj[x][y]);
        bm2-=(bm2&(-bm2));
    }
    return memo[x][bm]=ans;
}

long long plan_roller_coaster(vector<int> s, vector<int> t) {
    int n=(int)s.size();
    if(n>16){
        vector<pair<int,int> > S,T;
        for(int i=0;i<n;i++){
            S.push_back(make_pair(s[i],i));
            T.push_back(make_pair(t[i],i));
        }
        sort(S.begin(),S.end()); sort(T.begin(),T.end());
        int pos[n];
        for(int i=0;i<n;i++){
            pos[S[i].second]=i;
        }
        for(int i=n-1;i>=0;i--){
            if(pos[T[i].second]>=i){
                if(s[T[i].second-1]<T[i].first){
                    return 1;
                }
                ///do something with T[i].second-1
            }else{
                if(s[T[i].second]<T[i].first){
                    return 1;
                }
                ///do something with T[i].second
            }
        }
        return 0;
    }
    for(int i=0;i<n;i++){
        for(int j=0;j<n;j++){
            if(i==j)adj[i][j]=0;
            else adj[i][j]=max(0,t[i]-s[j]);
        }
    }
    memset(memo,-1,sizeof(memo));
    long long ans=4000000000000000010;
    for(int i=0;i<n;i++){
        ans=min(ans,tsp(i,(1<<n)-1-(1<<i)));
    }
    return ans;
}

• Subtask 1: 11 / 11
• Subtask 2: 23 / 23
• Subtask 3: 0 / 30
• Subtask 4: 0 / 36