Submission #121168

#	Time	Username	Problem	Language	Result	Execution time	Memory
121168		win11905	Roller Coaster Railroad (IOI16_railroad)	C++11	34 / 100	88 ms	9320 KiB

railroad

#include "railroad.h"
#include <bits/stdc++.h>
#define long long long 
#define pii pair<long, long>
#define x first
#define y second
using namespace std;

const int N = 16;

int n;
vector<int> s, t;
long dp[N][1<<N];

long solve(int u, int bit) {
    if(dp[u][bit] != -1) return dp[u][bit];
    if((bit ^ (1 << u)) == 0) return dp[u][bit] = 0;
    dp[u][bit] = 1e18;
    for(int i = 0; i < n; ++i) if(i != u && ((bit >> i) & 1)) {
        long val = (t[i] > s[u] ? (t[i] - s[u]) : 0) + solve(i, bit ^ (1 << u));
        dp[u][bit] = min(dp[u][bit], val);
    }
    return dp[u][bit];
}

long s1() {
    memset(dp, -1, sizeof dp);
    int bit = (1 << n) - 1;
    long ans = 1e18;
    for(int i = 0; i < n; ++i) ans = min(ans, solve(i, bit));
    return ans;
}

long s2() {
    vector<pii> vec;
    for(int i = 0; i < n; ++i) vec.emplace_back(s[i], t[i]);
    sort(vec.begin(), vec.end(), [&](const pii &a, const pii &b) { return a.y == b.y ? a.x < b.x : a.y < b.y; });
    for(int i = 1; i < n; ++i) if(vec[i-1].y > vec[i].x) return 1;
    return 0;
}

long plan_roller_coaster(vector<int> s, vector<int> t) {
    n = (int)s.size();
    ::s = s, ::t = t;
    return n <= 16 ? s1() : s2();
}

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