Submission #100021

#	Time	Username	Problem	Language	Result	Execution time	Memory
100021		shenxy	Roller Coaster Railroad (IOI16_railroad)	C++11	11 / 100	362 ms	25596 KiB

railroad

#include "railroad.h"
#include <algorithm>
#include <vector>
#include <map>
#include <utility>
#define INF 1E18
using namespace std;
int N;
long long int plan_roller_coaster(vector<int> s, vector<int> t) {
    N = s.size();
    if (N <= 8) {
        vector<int> u;
        for (int i = 0; i < 8; i++) {
            u.push_back(i);
        }
        long long int ans = 0;
        for (int i = 1; i < 8; i++) {
            ans += max(0, t[u[i - 1]] - s[u[i]]);
        }
        while (next_permutation(u.begin(), u.end())) {
            long long int temp = 0;
            for (int i = 1; i < 8; i++) {
                temp += max(0, t[u[i - 1]] - s[u[i]]);
            }
            ans = min(ans, temp);
        }
        return ans;
    }
    multimap<int, int> mymap;
    for (int i = 0; i < N; i++) {
        mymap.insert({s[i], t[i]});
    }
    int nowspeed = mymap.begin() -> second;
    mymap.erase(mymap.begin());
    while (!mymap.empty()) {
        multimap<int, int>::iterator it = mymap.lower_bound(nowspeed);
        if (it == mymap.end()) return 1;
        nowspeed = it -> second;
        if (mymap.lower_bound(nowspeed) == mymap.end()) {
            it++;
            if (it != mymap.end()) nowspeed = it -> second;
        }
        mymap.erase(it);
    }
    return 0;
}

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