Submission #290121

#	Time	Username	Problem	Language	Result	Execution time	Memory
290121		evpipis	Rectangles (IOI19_rect)	C++14	72 / 100	5088 ms	460800 KiB

rect

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

#define fi first
#define se second
#define pb push_back
#define mp make_pair

typedef long long ll;
typedef pair<int, int> ii;
typedef vector<ii> inter;

const int len = 2505;
int po[len], mat[len][len], n, m;
inter row_inter[len], col_inter[len];

void print(inter now){
    for (int i = 0; i < now.size(); i++)
        printf(" (%d, %d)\n", now[i].fi, now[i].se);
    printf("\n");
}

inter make_inter(vector<int> vec){
    inter res;

    vector<int> stck;
    for (int i = 0; i < vec.size(); i++){
        while (!stck.empty() && vec[i] > vec[stck.back()])
            stck.pop_back();

        if (!stck.empty() && stck.back() < i-1)
            res.pb(mp(stck.back()+1, i-1));

        stck.pb(i);
    }

    stck.clear();
    for (int i = (int)vec.size()-1; i >= 0; i--){
        while (!stck.empty() && vec[i] > vec[stck.back()])
            stck.pop_back();

        if (!stck.empty() && stck.back() > i+1)
            res.pb(mp(i+1, stck.back()-1));

        stck.pb(i);
    }

    sort(res.begin(), res.end());
    res.erase(unique(res.begin(), res.end()), res.end());
    return res;
}

inter join(inter &fir, inter &sec){
    inter res;

    for (int i = 0, j = 0; i < fir.size(); i++){
        while (j < sec.size() && sec[j] < fir[i])
            j++;

        if (j < sec.size() && sec[j] == fir[i])
            res.pb(fir[i]);
    }

    return res;
}

struct{
    struct rec{
        int ar, br, ac, bc;

        rec(int ar_ = len, int br_ = 0, int ac_ = len, int bc_ = 0){
            ar = ar_;
            br = br_;
            ac = ac_;
            bc = bc_;
        }

        void upd(rec other){
            ar = min(ar, other.ar);
            br = max(br, other.br);
            ac = min(ac, other.ac);
            bc = max(bc, other.bc);
        }

        int area(){
            return (br-ar+1) * (bc-ac+1);
        }
    };

    int dr[4] = {0, 0, 1, -1}, dc[4] = {1, -1, 0, 0};
    int vis[len][len];

    int dfs(int x, int y, rec &tot){
        vis[x][y] = 1;
        int cnt = 1;
        tot.upd(rec(x, x, y, y));

        for (int d = 0; d < 4; d++){
            int i = x+dr[d];
            int j = y+dc[d];
            if (i >= 0 && i < n && j >= 0 &&  j < m && mat[i][j] == 0 && !vis[i][j])
                cnt += dfs(i, j, tot);
        }

        return cnt;
    }

    int solve(){
        int ans = 0;
        for (int i = 0; i < n; i++)
            for (int j = 0; j < m; j++)
                if (!vis[i][j] && mat[i][j] == 0){
                    rec temp;
                    int cnt = dfs(i, j, temp);
                    if (temp.ar > 0 && temp.br < n-1 && temp.ac > 0 && temp.bc < m-1 && temp.area() == cnt)
                        ans++;
                }

        return ans;
    }
} subtask6;

ll count_rectangles(vector<vector<int> > M) {
    n = M.size(), m = M[0].size();

    int sub6 = 1;
    for (int i = 0; i < n; i++)
        for (int j = 0; j < m; j++){
            mat[i][j] = M[i][j];
            if (mat[i][j] > 1) sub6 = 0;
        }

    if (sub6)
        return subtask6.solve();
    //printf("n = %d, m = %d\n", n, m);
    for (int i = 0; i < n; i++){
        vector<int> vec;
        for (int j = 0; j < m; j++)
            vec.pb(mat[i][j]);
        row_inter[i] = make_inter(vec);

        //printf("row = %d\n", i);
        //print(row_inter[i]);
    }

    for (int j = 0; j < m; j++){
        vector<int> vec;
        for (int i = 0; i < n; i++)
            vec.pb(mat[i][j]);
        col_inter[j] = make_inter(vec);

        //printf("col = %d\n", j);
        //print(col_inter[j]);
    }

    ll ans = 0;
    for (int st_row = 0; st_row < n; st_row++){
        inter cur = row_inter[st_row];
        for (int j = 0; j < m; j++)
            po[j] = 0;

        for (int en_row = st_row; en_row < n; en_row++){
            vector<int> can(m, 0);
            for (int j = 0; j < m; j++){
                while (po[j] < col_inter[j].size() && col_inter[j][po[j]] < mp(st_row, en_row))
                    po[j]++;
                if (po[j] < col_inter[j].size() && col_inter[j][po[j]] == mp(st_row, en_row))
                    can[j] = 1;
            }

            for (int j = 1; j < m; j++)
                can[j] += can[j-1];

            if (en_row != st_row)
                cur = join(cur, row_inter[en_row]);

            // upd ans
            for (auto in: cur){
                if (can[in.se]-can[in.fi-1] == in.se-in.fi+1)
                    ans++; //, printf("st = %d, en = %d, in = (%d, %d)\n", st_row, en_row, in.fi, in.se);
            }
        }
    }

	return ans;
}

/*
10 10
3 2 2 2 5 1 1 1 1 1
3 1 1 1 2 1 1 1 1 1
6 2 2 2 3 1 1 1 1 1
1 1 1 1 1 1 1 1 1 1
1 1 1 1 1 1 1 1 1 1
1 1 1 1 1 1 1 1 1 1
1 1 1 1 1 1 1 1 1 1
1 1 1 1 1 1 1 1 1 1
1 1 1 1 1 1 1 1 1 1
1 1 1 1 1 1 1 1 1 1
*/

Compilation message (stderr)

rect.cpp: In function 'void print(inter)':
rect.cpp:19:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   19 |     for (int i = 0; i < now.size(); i++)
      |                     ~~^~~~~~~~~~~~
rect.cpp: In function 'inter make_inter(std::vector<int>)':
rect.cpp:28:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   28 |     for (int i = 0; i < vec.size(); i++){
      |                     ~~^~~~~~~~~~~~
rect.cpp: In function 'inter join(inter&, inter&)':
rect.cpp:57:30: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   57 |     for (int i = 0, j = 0; i < fir.size(); i++){
      |                            ~~^~~~~~~~~~~~
rect.cpp:58:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   58 |         while (j < sec.size() && sec[j] < fir[i])
      |                ~~^~~~~~~~~~~~
rect.cpp:61:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   61 |         if (j < sec.size() && sec[j] == fir[i])
      |             ~~^~~~~~~~~~~~
rect.cpp: In function 'll count_rectangles(std::vector<std::vector<int> >)':
rect.cpp:166:30: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  166 |                 while (po[j] < col_inter[j].size() && col_inter[j][po[j]] < mp(st_row, en_row))
      |                        ~~~~~~^~~~~~~~~~~~~~~~~~~~~
rect.cpp:168:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  168 |                 if (po[j] < col_inter[j].size() && col_inter[j][po[j]] == mp(st_row, en_row))
      |                     ~~~~~~^~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 8 / 8
• Subtask 2: 7 / 7
• Subtask 3: 12 / 12
• Subtask 4: 22 / 22
• Subtask 5: 10 / 10
• Subtask 6: 13 / 13
• Subtask 7: 0 / 28