Submission #296615

#	Time	Username	Problem	Language	Result	Execution time	Memory
296615		Osama_Alkhodairy	Rectangles (IOI19_rect)	C++17	59 / 100	2198 ms	1048580 KiB

rect

#include <bits/stdc++.h>
#include "rect.h"
//~ #include "grader.cpp"
using namespace std;
#define ll long long

const int N = 2501;
const int INF = (int)1e9;

struct segment{
    pair <int, int> tree[4 * N];
    //~ mn, mx
    segment(){
        for(int i = 0 ; i < 4 * N ; i++){
            tree[i] = make_pair(INF, -INF);
        }
    }
    pair <int, int> merge(pair <int, int> l, pair <int, int> r){
        return make_pair(min(l.first, r.first), max(l.second, r.second));
    }
    void build(int l, int r, int node, vector <int> &a){
        if(l == r){
            if(a[l] != -1){
                tree[node] = make_pair(a[l], a[l]);
            }
            return;
        }
        int mid = (l + r) / 2;
        build(l, mid, 2 * node, a);
        build(mid + 1, r, 2 * node + 1, a);
        tree[node] = merge(tree[2 * node], tree[2 * node + 1]);
    }
    pair <int, int> query(int l, int r, int node, int s, int e){
        if(r < l || r < s || l > e) return make_pair(INF, -INF);
        if(s <= l && r <= e) return tree[node];
        int mid = (l + r) / 2;
        return merge(query(l, mid, 2 * node, s, e), query(mid + 1, r, 2 * node + 1, s, e));
    }
};

int n, m;
vector <vector <int> > a;
set <pair <pair <int, int>, pair <int, int> > > vis;
vector <vector <int> > us, rs, ds, ls, ue, re, de, le;
vector <segment> ue_tree, re_tree, de_tree, le_tree;

vector <int> calc(vector <int> &a, int b, int c){
    //~ b = 0 for >
    //~ b = 1 for >=
    //~ c = 0 for forward
    //~ c = 1 for backward
    int n = a.size();
    vector <int> inds;
    for(int i = 0 ; i < n ; i++){
        if(c == 0) inds.push_back(i);
        else inds.push_back(n - i - 1);
    }
    vector <int> ret(n);
    vector <int> cur;
    for(auto &i : inds){
        while(cur.size() && a[i] >= a[cur.back()] + b){
            cur.pop_back();
        }
        if(cur.size() == 0) ret[i] = -1;
        else ret[i] = cur.back();
        cur.push_back(i);
    }
    return ret;
}
bool check(int r1, int c1, int r2, int c2){
    if(r1 == -1 || c1 == -1 || r2 == -1 || c2 == -1) return 0;
    if(vis.count(make_pair(make_pair(r1, c1), make_pair(r2, c2)))) return 0;
    vis.insert(make_pair(make_pair(r1, c1), make_pair(r2, c2)));
    int v = de_tree[r1].query(0, m - 1, 1, c1 + 1, c2 - 1).first;
    if(v < r2) return 0;
    v = ue_tree[r2].query(0, m - 1, 1, c1 + 1, c2 - 1).second;
    if(v > r1) return 0;
    v = re_tree[c1].query(0, n - 1, 1, r1 + 1, r2 - 1).first;
    if(v < c2) return 0;
    v = le_tree[c2].query(0, n - 1, 1, r1 + 1, r2 - 1).second;
    if(v > c1) return 0;
    return 1;
}
long long count_rectangles(std::vector<std::vector<int> > A) {
    a = A;
    n = a.size();
    m = a[0].size();
    us.resize(n, vector <int>(m));
    ue.resize(n, vector <int>(m));
    ds.resize(n, vector <int>(m));
    de.resize(n, vector <int>(m));
    ls.resize(n, vector <int>(m));
    le.resize(n, vector <int>(m));
    rs.resize(n, vector <int>(m));
    re.resize(n, vector <int>(m));
    ue_tree.resize(n);
    de_tree.resize(n);
    le_tree.resize(m);
    re_tree.resize(m);
    for(int i = 0 ; i < n ; i++){
        vector <int> cur = a[i];
        ls[i] = calc(cur, 0, 0);
        le[i] = calc(cur, 1, 0);
        rs[i] = calc(cur, 0, 1);
        re[i] = calc(cur, 1, 1);
    }
    for(int j = 0 ; j < m ; j++){
        vector <int> cur(n);
        for(int i = 0 ; i < n ; i++){
            cur[i] = a[i][j];
        }
        vector <int> g;
        g = calc(cur, 0, 0);
        for(int i = 0 ; i < n ; i++){
            us[i][j] = g[i];
        }
        g = calc(cur, 1, 0);
        for(int i = 0 ; i < n ; i++){
            ue[i][j] = g[i];
        }
        g = calc(cur, 0, 1);
        for(int i = 0 ; i < n ; i++){
            ds[i][j] = g[i];
        }
        g = calc(cur, 1, 1);
        for(int i = 0 ; i < n ; i++){
            de[i][j] = g[i];
        }
    }
    for(int i = 0 ; i < n ; i++){
        ue_tree[i].build(0, m - 1, 1, ue[i]);
        de_tree[i].build(0, m - 1, 1, de[i]);
    }
    for(int j = 0 ; j < m ; j++){
        vector <int> cur(n);
        for(int i = 0 ; i < n ; i++){
            cur[i] = le[i][j];
        }
        le_tree[j].build(0, n - 1, 1, cur);
        cur.assign(n, 0);
        for(int i = 0 ; i < n ; i++){
            cur[i] = re[i][j];
        }
        re_tree[j].build(0, n - 1, 1, cur);
    }
    int ret = 0;
    for(int i = 0 ; i < n ; i++){
        for(int j = 0 ; j < m ; j++){
            ret += check(us[i][j], ls[i][j], ds[i][j], rs[i][j]);
        }
    }
    return ret;
}

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