Submission #1222493

#	Time	Username	Problem	Language	Result	Execution time	Memory
1222493		Ariadna	Naval battle (CEOI24_battle)	C++20	76 / 100	2987 ms	1114112 KiB

Main

#include <bits/stdc++.h>
using namespace std;

char dir[4] = {'N', 'S', 'E', 'W'};

struct Ship {
    int x, y, d;
    pair<int, int> move;
    void init() {
        if (d == 0) move = {0, -1};
        else if (d == 1) move = {0, 1};
        else if (d == 2) move = {1, 0};
        else move = {-1, 0};
    }
};

void solve1(int n, vector<Ship>& s) {
    vector<pair<int, pair<int, int>>> collision;
    for (int i = 0; i < n; ++i) {
        for (int j = 0; j < n; ++j) {
            int col = (abs(s[i].x-s[j].x)+abs(s[i].y-s[j].y))/2;
            if (s[i].x == s[j].x) {
                if (s[i].d == 0 && s[j].d == 1) {
                    if (s[i].y > s[j].y) collision.push_back({col, {i, j}});
                } else if (s[i].d == 1 && s[j].d == 0) {
                    if (s[i].y < s[j].y) collision.push_back({col, {i, j}});
                }
            } else if (s[i].y == s[j].y) {
                if (s[i].d == 2 && s[j].d == 3) {
                    if (s[i].x < s[j].x) collision.push_back({col, {i, j}});
                } else if (s[i].d == 3 && s[j].d == 2) {
                    if (s[i].x > s[j].x) collision.push_back({col, {i, j}});
                }
            } else if (s[i].x+s[i].y == s[j].x+s[j].y) {
                if (s[i].d == 0) {
                    if (s[j].d == 3 && s[j].x > s[i].x) collision.push_back({col, {i, j}});
                } else if (s[i].d == 1) {
                    if (s[j].d == 2 && s[j].x < s[i].x) collision.push_back({col, {i, j}});
                } else if (s[i].d == 2) {
                    if (s[j].d == 1 && s[j].x > s[i].x) collision.push_back({col, {i, j}});
                } else {
                    if (s[j].d == 0 && s[j].x < s[i].x) collision.push_back({col, {i, j}});
                }
            } else if (s[i].x-s[i].y == s[j].x-s[j].y) {
                if (s[i].d == 0) {
                    if (s[j].d == 2 && s[j].x < s[i].x) collision.push_back({col, {i, j}});
                } else if (s[i].d == 1) {
                    if (s[j].d == 3 && s[j].x > s[i].x) collision.push_back({col, {i, j}});
                } else if (s[i].d == 2) {
                    if (s[j].d == 0 && s[j].x > s[i].x) collision.push_back({col, {i, j}});
                } else {
                    if (s[j].d == 1 && s[j].x < s[i].x) collision.push_back({col, {i, j}});
                }
            }
        }
    }

    sort(collision.begin(), collision.end());
    int m = (int)collision.size();

    vector<bool> sink(n, false);

    int act_col = -1;
    vector<int> aux;
    for (int i = 0; i < m; ++i) {
        int col = collision[i].first, i1 = collision[i].second.first, i2 = collision[i].second.second;
        if (col != act_col) {
            for (int a: aux) sink[a] = true;
            aux = {};
            act_col = col;
        }

        if (!sink[i1] && !sink[i2]) {
            aux.push_back(i1);
            aux.push_back(i2);
        }
    }

    for (int i: aux) sink[i] = true;

    for (int i = 0; i < n; ++i) {
        if (!sink[i]) cout << i+1 << endl;
    }
}

void solve2(int n, vector<Ship>& s) {
    map<int, int> comp;
    set<int> diagonals;
    for (int i = 0; i < n; ++i) diagonals.insert(s[i].x+s[i].y);

    int cnt = 0;
    for (int a: diagonals) {
        comp[a] = cnt;
        ++cnt;
    }

    int m = (int)diagonals.size();
    vector<vector<pair<int, int>>> D(m);
    for (int i = 0; i < n; ++i) { 
        D[comp[s[i].x+s[i].y]].push_back({s[i].x, i});
    }

    vector<bool> sink(n, false);
    for (int i = 0; i < m; ++i) {
        sort(D[i].begin(), D[i].end());
        vector<int> v;
        for (int j = 0; j < (int)D[i].size(); ++j) {
            int idx = D[i][j].second;
            if (s[idx].d == 1) {
                if (!v.empty()) {
                    sink[idx] = true;
                    int idx2 = v[(int)v.size()-1];
                    sink[idx2] = true;
                    v.pop_back();
                }
               
            } else v.push_back(idx);
        }
    }

    for (int i = 0; i < n; ++i) {
        if (!sink[i]) cout << i+1 << endl;
    }
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(NULL);

    int n;
    cin >> n;
    vector<Ship> s(n);
    bool N = false, W = false;
    for (int i = 0; i < n; ++i) {
        int x, y, d;
        char c;
        cin >> x >> y >> c;
        if (c == 'N') {
            d = 0;
            N = true;
        } else if (c == 'S') d = 1;
        else if (c == 'E') d = 2;
        else {
            d = 3;
            W = true;
        }
        s[i].x = x;
        s[i].y = y;
        s[i].d = d;
        s[i].init();
    }

    if (N||W) solve1(n, s);
    else solve2(n, s);
    
    return 0;
}

• Subtask 0: 0 / 0
• Subtask 1: 6 / 6
• Subtask 2: 12 / 12
• Subtask 3: 8 / 8
• Subtask 4: 11 / 11
• Subtask 5: 9 / 9
• Subtask 6: 30 / 30
• Subtask 7: 0 / 24