Submission #595057

#	Time	Username	Problem	Language	Result	Execution time	Memory
595057		Lucpp	Roller Coaster Railroad (IOI16_railroad)	C++17	34 / 100	263 ms	28432 KiB

railroad

#include "railroad.h"
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const ll INF = 1e18;

set<pair<int, int>> byS;

int calc(int s, int t){
    byS.erase(make_pair(s, t));
    if(byS.empty()) return 0;
    auto it = byS.lower_bound(make_pair(t, 0));
    if(it == byS.end()){
        byS.emplace(s, t);
        return -1;
    }
    int code = calc(it->first, it->second);
    if(code == -2) return -2;
    if(code == -1){
        it = ++byS.lower_bound(make_pair(t, 0));
        if(it == byS.end() || calc(it->first, it->second) < 0) return -2;
    }
    return 0;
}

ll plan_roller_coaster(vector<int> s, vector<int> t) {
    int n = (int)s.size();
    if(n <= 16){
        vector<vector<ll>> dp(1<<n, vector<ll>(n));
        for(int msk=1; msk < (1<<n); msk++){
            if(__builtin_popcount(msk) == 1) continue;
            for(int i = 0; i < n; i++){
                if(!(msk & (1<<i))) continue;
                dp[msk][i] = INF;
                int m = msk^(1<<i);
                for(int j = 0; j < n; j++){
                    if(!(m & (1<<j))) continue;
                    dp[msk][i] = min(dp[msk][i], dp[m][j] + max(0, t[j]-s[i]));
                }
            }
        }
        ll ans = INF;
        for(int i = 0; i < n; i++) ans = min(ans, dp[(1<<n)-1][i]);
        return ans;
    }
    else{
        for(int i = 0; i < n; i++) byS.emplace(s[i], t[i]);
        int code = calc(s[0], t[0]);
        if(code == -1) code = calc(s[1], t[1]);
        if(code < 0) return 1;
        else return 0;
    }
}

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