Submission #659099

#	Time	Username	Problem	Language	Result	Execution time	Memory
659099		Jeff12345121	Tram (CEOI13_tram)	C++14	45 / 100	1086 ms	2440 KiB

tram

    #include <bits/stdc++.h>
    #define REP(i,n) for(int i = 1; i <= (n); i++)
    using namespace std;

    #ifdef LOCAL
    ifstream in("in.in");
    ofstream out("out.out");
    #else
    #define in cin
    #define out cout
    #endif

    ///brute

    int n,m;
    const int nmax = 150005,inf = 1000000005;
    pair<int,int> queries[nmax];
    int a[nmax][3];
    set<pair<int,int>> s;
    set<int> dis_s[2];

    int squared(int x) {
        return x * x;
    }
    int find_distance(int y, int x, int i, int j) {
        return squared(y - i) + squared(x - j);
    }
    int get_dis(int y, int x) {
        int val[3] = {inf,inf,inf};///min dis from some other value
        for (int k = 1; k <= 2; k++) {
            auto after = dis_s[k - 1].lower_bound(y);
            auto before = after;
            if (before != dis_s[k - 1].begin()) {
                before--;
                val[k] = min(val[k], find_distance(k , *before , x, y));
            }
            if (after != dis_s[k - 1].end()) {
                val[k] = min(val[k], find_distance(k , *after , x, y));
            }
        }
        return min(val[1] ,val[2]);
    }
    pair<int,int> add() {
        pair<int,int> sol;
        int max_dis = -inf;

        if (s.empty()) {
            return {1,1};
        }
        auto check = [&](int i, int j) {
            if ((1 <= i && i <= n && 1 <= j && j <= n) && a[i][j] == 0) {
                int dis = get_dis(i,j);
                if (dis > max_dis) {
                    max_dis = dis;
                    sol = {i,j};
                } else if (dis == max_dis && (pair<int,int>{i,j}) < sol) {
                    sol = {i,j};
                }
            }
        };

        auto handle = [&](int y1, int y2) {
            for (int j = 1; j <= 2; j++) {
                check(y1,j);
                check(y2,j);
            }
                /// now check the inbetween spot.
            vector<int> mids;
            mids.push_back((y1 + y2) / 2);
            if ((y1 + y2) %2 == 1) {
                mids.push_back((y1 + 2)/2 + 1);
            }
            for (auto k : mids) {
                for (int j = 1; j <= 2; j++) {
                    check(k,j);
                    check(k-1,j);
                    check(k+1,j);
                }
            }
        };

        for (auto it = s.begin(); it != s.end(); it++) {
            auto nxt = it;
            nxt++;

            if (nxt != s.end()) {
                handle(it->first, nxt->first);
            } else {
                handle(it->first,n);
            }

        }

        handle(1 , s.begin()->first);

        return sol;
    }

    pair<int,int> i_to_pair(int i) {
        int s = 0;
        return {i,a[i][1] + 2 * a[i][2]};
    }
    int main() {
        in >> n >> m;
        for (int i = 1; i <= m; i++) {
            char type;
            in >> type;
            if (type == 'E') {
                pair<int,int> pos = add();
                s.erase(i_to_pair(pos.first));
                out << pos.first << " " << pos.second << "\n";
                a[pos.first][pos.second] = 1;
                dis_s[pos.second - 1].insert(pos.first);
                
                s.insert(i_to_pair(pos.first));
                queries[i] = pos;
            } else {
                int pos;
                in >> pos;
                int y = queries[pos].first,x = queries[pos].second; 
                s.erase(i_to_pair(y));
                dis_s[queries[pos].second - 1].erase(queries[pos].first);

                a[y][x] = 0;
                if (a[y][1] == 1 ||  a[y][2] == 1) {
                    s.insert(i_to_pair(y));
                }           
            }
        }
    }

Compilation message (stderr)

tram.cpp: In function 'std::pair<int, int> i_to_pair(int)':
tram.cpp:100:13: warning: unused variable 's' [-Wunused-variable]
  100 |         int s = 0;
      |             ^

• Subtask 1: 10 / 10
• Subtask 2: 15 / 15
• Subtask 3: 10 / 10
• Subtask 4: 10 / 10
• Subtask 5: 0 / 10
• Subtask 6: 0 / 10
• Subtask 7: 0 / 15
• Subtask 8: 0 / 20