Submission #99986

#	Time	Username	Problem	Language	Result	Execution time	Memory
99986		jamielim	Roller Coaster Railroad (IOI16_railroad)	C++14	0 / 100	2041 ms	12872 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){
        set<pair<int,int> > st;
        for(int i=0;i<n;i++)st.insert(make_pair(s[i],t[i]));
        int cur=1;
        while(!st.empty()){
            set<pair<int,int> >::iterator it=st.lower_bound(make_pair(cur,-1));
            if(it==st.end())return 0;
            cur=it->second;
            --it;
        }
        return 1;
    }
    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]);
        }
    }
    for(int i=0;i<n;i++){
        for(int j=0;j<n;j++){
            for(int k=0;k<n;k++){
                adj[j][k]=min(adj[j][k],adj[j][i]+adj[i][k]);
            }
        }
    }
    memset(memo,-1,sizeof(memo));
    long long ans=1000000000000000010;
    for(int i=0;i<n;i++){
        ans=min(ans,tsp(i,(1<<n)-1-(1<<i)));
    }
    return ans;
}

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