Submission #1178818

#	Time	Username	Problem	Language	Result	Execution time	Memory
1178818		ericl23302	Aliens (IOI16_aliens)	C++20	4 / 100	5 ms	328 KiB

aliens

#include "aliens.h"

#include <iostream>
#include <algorithm>
#include <utility>
#include <climits>
#include <set>
using namespace std;

long long sq(long long a) {
    return a * a;
}
long long sq(int a) {
    return (long long)(a) * a;
}

long long getArea(pair<int, int> a) {
    return sq(a.second - a.first + 1);
}
long long getArea(int a, int b) {
    return sq(b - a + 1);
}

long long intersection(pair<int, int> a, pair<int, int> b) {
    return sq(max(0, min(a.second, b.second) - max(a.first, b.first) + 1));
}

long long unite(pair<int, int> a, pair<int, int> b) {
    return getArea(min(a.first, b.first), max(a.second, b.second));
}

long long take_photos(int n, int m, int k, std::vector<int> r, std::vector<int> c) {
    set<pair<int, int>> curPoints;
    for (int i = 0; i < n; ++i) curPoints.emplace(min(r[i], c[i]), max(r[i], c[i]));
    long long leastCost = LLONG_MAX / 2;
    while (curPoints.size() > k) {
        leastCost = LLONG_MAX / 2;
        auto curStart = curPoints.end(), curEnd = curPoints.end();
        for (auto i = curPoints.begin(); i != curPoints.end(); ++i) {
            for (auto j = next(i); j != curPoints.end(); ++j) {
                auto a = *i, b = *j;
                long long curCost = unite(a, b) - getArea(a) - getArea(b) + intersection(a, b);
                if (curCost < leastCost) {
                    leastCost = curCost;
                    curStart = i; 
                    curEnd = j;
                }
            }
        }

        auto a = *curStart, b = *curEnd;
        pair<int, int> newRange = make_pair(min(a.first, b.first), max(a.second, b.second));
        curPoints.erase(curStart);
        curPoints.erase(curEnd);
        curPoints.insert(newRange);
    }

    vector<pair<int, int>> condensedPoints;
    int curBegin = -1, curEnd = -1;
    for (auto i = curPoints.begin(); i != curPoints.end(); ++i) {
        auto a = *i;
        if (a.first == curBegin) curEnd = max(curEnd, a.second);
        else {
            if (curBegin != -1) condensedPoints.emplace_back(curBegin, curEnd);
            curBegin = a.first;
            curEnd = a.second;
        }
    }
    condensedPoints.emplace_back(curBegin, curEnd);
    auto a = condensedPoints[0];
    long long res = getArea(a);
    for (int i = 1; i < condensedPoints.size(); ++i) {
        auto b = condensedPoints[i];
        if (b.second <= a.second) {
            continue;
        } else {
            res += getArea(b) - intersection(a, b);
            a = b;
        }
    }

    return res;
}

Compilation message (stderr)

aliens.h:1:9: warning: #pragma once in main file
    1 | #pragma once
      |         ^~~~
aliens_c.h:1:9: warning: #pragma once in main file
    1 | #pragma once
      |         ^~~~

• Subtask 1: 4 / 4
• Subtask 2: 0 / 12
• Subtask 3: 0 / 9
• Subtask 4: 0 / 16
• Subtask 5: 0 / 19
• Subtask 6: 0 / 40