Submission #65962

#	Time	Username	Problem	Language	Result	Execution time	Memory
65962		gs13068	Roller Coaster Railroad (IOI16_railroad)	C++17	100 / 100	319 ms	158168 KiB

railroad

#include "railroad.h"
#include <algorithm>
 
using namespace std;
 
int x[400004], xn;
int a[400004];
int p[400004];
pair<int, pair<int, int> > d[400004];
int dn;
 
int f(int x) {
    return x == p[x] ? x : p[x] = f(p[x]);
}
 
long long plan_roller_coaster(std::vector<int> s, std::vector<int> t) {
    long long r = 0;
    int n = (int) s.size();
    int i;
    for (i = 0; i < n; i++) {
        x[xn++] = s[i];
        x[xn++] = t[i];
    }
    sort(x, x + xn);
    xn = unique(x, x + xn) - x;
    for (i = 0; i <= xn; i++) p[i] = i;
    for (i = 0; i < n; i++) {
        s[i] = lower_bound(x, x + xn, s[i]) - x;
        t[i] = lower_bound(x, x + xn, t[i]) - x;
        a[s[i]]++, a[t[i]]--;
        p[f(s[i])] = f(t[i]);
    }
    for (i = 0; i < xn; i++) {
        a[i + 1] += a[i];
        if (a[i] != 1) {
            p[f(i)] = f(i + 1);
            if (a[i] > 1) r += (a[i] - 1ll) * (x[i + 1] - x[i]);
        }
        else {
            d[dn].first = x[i + 1] - x[i];
            d[dn].second.first = i;
            d[dn].second.second = i + 1;
            dn++;
        }
    }
    sort(d, d + dn);
    for (i = 0; i < dn; i++) if (f(d[i].second.first) != f(d[i].second.second)) {
        r += d[i].first;
        p[f(d[i].second.first)] = d[i].second.second;
    }
    return r;
}

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