Submission #100072

#	Time	Username	Problem	Language	Result	Execution time	Memory
100072		dantoh000	Roller Coaster Railroad (IOI16_railroad)	C++14	34 / 100	194 ms	9180 KiB

railroad

#include "railroad.h"
#include <bits/stdc++.h>
#define INF 1e18
using namespace std;
typedef pair<int,int> ii;
int n;
vector<int> s, t;
long long memo[17][65537];
long long dp(int id, int mask){
    //printf("%lld %lld\n",id,mask);
    if (mask == (1<<n) - 1) return 0;
    if (memo[id][mask] != -1) return memo[id][mask];
    memo[id][mask] = INF;
    for (int i = 0; i < n; i++){
        if (!(mask&(1<<i))){
            memo[id][mask] = min(memo[id][mask],dp(i,(mask|(1<<i)))+max(0,t[id]-s[i]));
        }
    }
    return memo[id][mask];
}

long long plan_roller_coaster(vector<int> t1, vector<int> t2) {
    n = (int) t1.size();
    for (int i = 0; i < n; i++){
        s.push_back(t1[i]);
        t.push_back(t2[i]);
    }
    vector<ii> s0,t0;
    for (int i = 1; i <= n; i++){
        s0.push_back(ii(t1[i-1],i));
        t0.push_back(ii(t2[i-1],i));
    }
    s0.push_back(ii(1000000001,n+1));
    t0.push_back(ii(0,0));
    long long ans = INF;
    if (n <= 16){
        memset(memo,-1,sizeof(memo));
        for (int i = 0; i < n; i++){
            ans = min(ans,dp(i,1<<i));
        }
    }
    else{
        sort(s0.begin(),s0.end(),greater<ii>());
        sort(t0.begin(),t0.end(),greater<ii>());
        int order[n+2];
        for (int i = 0; i < t0.size(); i++){
            //printf("%d -> %d\n", t0[i].second, s0[i].second);
            if (t0[i].first >  s0[i].first) {
                return 1;
            }
            order[t0[i].second] = s0[i].second;
        }
        int cur = -1;
        int curid = 0;
        while (curid != n+1){
            //printf("%d\n",curid);
            curid = order[curid];
            cur++;
        }
        //printf("%d\n",cur);
        if (cur != n) return 1;
        return 0;
    }
    return ans;
}

Compilation message (stderr)

railroad.cpp: In function 'long long int plan_roller_coaster(std::vector<int>, std::vector<int>)':
railroad.cpp:46:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (int i = 0; i < t0.size(); i++){
                         ~~^~~~~~~~~~~

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