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Submission #600081

# Submission time Handle Problem Language Result Execution time Memory
600081 2022-07-20T12:44:01 Z Valaki2 Fountain Parks (IOI21_parks) C++17
15 / 100
 3500 ms 185284 KB 
#include "parks.h"
#include <bits/stdc++.h>
using namespace std;

#define x X
#define y Y

#define pb push_back
#define mp make_pair
#define pii pair<int, int>
#define fi first
#define se second

const int maxn = 2e5;
const vector<pii > directions = {mp(-2, 0), mp(0, -2), mp(0, 2), mp(2, 0)};

bool check_possibility(int n, vector<int> x, vector<int> y) {
    unordered_map<int, unordered_map<int, bool> > m;
    unordered_map<int, unordered_map<int, int> > f;
    for(int i = 0; i < n; i++) {
        f[x[i]][y[i]] = i + 1;
    }
    queue<int> q;
    q.push(0);
    m[x[0]][y[0]] = true;
    int cnt = 0;
    while(!q.empty()) {
        int cur = q.front();
        q.pop();
        cnt++;
        for(pii dir : directions) {
            pii new_point = mp(x[cur] + dir.fi, y[cur] + dir.se);
            if(f[new_point.fi][new_point.se] && !m[new_point.fi][new_point.se]) {
                m[new_point.fi][new_point.se] = true;
                int new_id = f[new_point.fi][new_point.se] - 1;
                q.push(new_id);
            }
        }
    }
    return (cnt == n);
}

struct fountain {
    int x, y, id;
    fountain() : x(0), y(0), id(-1) {}
    fountain(int x_, int y_, int id_) :
        x(x_), y(y_), id(id_) {}
};

int n;
vector<fountain > points;
vector<int> x;
vector<int> y;
unordered_map<int, unordered_map<int, int> > fountain_at;

unordered_map<int, unordered_map<int, bool> > bench_at;
unordered_map<int, unordered_map<int, bool> > road_at;
vector<int> ans_u;
vector<int> ans_v;
vector<int> ans_a;
vector<int> ans_b;

void build_road_bench(int road_u, int road_v, pii bench_pos) {
    ans_u.pb(road_u);
    ans_v.pb(road_v);
    ans_a.pb(bench_pos.fi);
    ans_b.pb(bench_pos.se);
    bench_at[bench_pos.fi][bench_pos.se] = true;
    road_at[(points[road_u].x + points[road_v].x) / 2][(points[road_u].y + points[road_v].y) / 2] = true;
}

vector<pii> get_bench_locations_pii(pii a, pii b) {
    fountain f_a = fountain(a.fi, a.se, -1), f_b = fountain(b.fi, b.se, -1);
    if(f_a.x == f_b.x) {
        int new_y = (f_a.y + f_b.y) / 2;
        a = mp(f_a.x + 1, new_y), b = mp(f_a.x - 1, new_y);
    } else {
        int new_x = (f_a.x + f_b.x) / 2;
        a = mp(new_x, f_a.y + 1), b = mp(new_x, f_a.y - 1);
    }
    return {min(a, b), max(a, b)};
}

vector<pii> get_bench_locations(int a_idx, int b_idx) {
    fountain f_a = points[a_idx], f_b = points[b_idx];
    pii a, b;
    if(f_a.x == f_b.x) {
        int new_y = (f_a.y + f_b.y) / 2;
        a = mp(f_a.x + 1, new_y), b = mp(f_a.x - 1, new_y);
    } else {
        int new_x = (f_a.x + f_b.x) / 2;
        a = mp(new_x, f_a.y + 1), b = mp(new_x, f_a.y - 1);
    }
    return {min(a, b), max(a, b)};
}

int get_middle_of_intersection(int a_idx, int b_idx) {
    pii a = mp(points[a_idx].x, points[a_idx].y);
    pii b = mp(points[b_idx].x, points[b_idx].y);
    int cnt = 0;
    for(pii dir : directions) {
        pii nei = mp(a.fi + dir.fi, a.se + dir.se);
        if(fountain_at[nei.fi][nei.se]) {
            cnt++;
        }
    }
    if(cnt == 4) {
        return a_idx;
    }
    cnt = 0;
    for(pii dir : directions) {
        pii nei = mp(b.fi + dir.fi, b.se + dir.se);
        if(fountain_at[nei.fi][nei.se]) {
            cnt++;
        }
    }
    if(cnt == 4) {
        return b_idx;
    }
    return -1;
}

pii get_bench_when_in_intersection(int a_idx, int b_idx) {
    // a is the middle, b is a neighbour
    fountain a = points[a_idx], b = points[b_idx];
    if(b.x < a.x) {
        return mp(a.x - 1, a.y + 1);
    }
    if(b.y < a.y) {
        return mp(a.x - 1, a.y - 1);
    }
    if(b.y > a.y) {
        return mp(a.x + 1, a.y + 1);
    }
    if(b.x > a.x) {
        return mp(a.x + 1, a.y - 1);
    }
}

pii orig;
unordered_map<int, unordered_map<int, bool> > not_bad;

bool bad_bench(pii bench, pii a, pii b) {
    if(not_bad[bench.fi][bench.se]) {
        return false;
    }
    if(a > b) {
        swap(a, b);
    }
    vector<pii > v = {a, b};
    for(pii dir : directions) {
        pii other = mp(bench.fi + dir.fi, bench.se + dir.se);
        vector<pii> corners = get_bench_locations_pii(bench, other);
        if(corners != v) {
            if(fountain_at[corners[0].fi][corners[0].se] &&
                fountain_at[corners[1].fi][corners[1].se] &&
                //bench_at[other.fi][other.se] &&
                !road_at[(bench.fi + other.fi) / 2][(bench.se + other.se) / 2]) {
                if(other == orig) {
                    not_bad[bench.fi][bench.se] = true;
                    return false;
                }
                if(bench_at[other.fi][other.se]) {
                    return true;
                } else {
                    return bad_bench(other, corners[0], corners[1]);
                }
            }
        }
    }
    not_bad[bench.fi][bench.se] = true;
    return false;
}

void solve() {
    unordered_map<int, unordered_map<int, bool> > vis;
    queue<int> q;
    q.push(0);
    vis[x[0]][y[0]] = true;
    while(!q.empty()) {
        int cur = q.front();
        q.pop();
        for(pii dir : directions) {
            pii new_point = mp(x[cur] + dir.fi, y[cur] + dir.se);
            if(fountain_at[new_point.fi][new_point.se] && !vis[new_point.fi][new_point.se]) {
                vis[new_point.fi][new_point.se] = true;
                int new_id = fountain_at[new_point.fi][new_point.se] - 1;
                q.push(new_id);
                int mid = get_middle_of_intersection(cur, new_id);
                if(mid != -1) {
                    build_road_bench(cur, new_id, get_bench_when_in_intersection(mid, cur ^ new_id ^ mid));
                } else {
                    vector<pii> benches = get_bench_locations(cur, new_id);
                    orig = benches[0];
                    if(!bench_at[benches[0].fi][benches[0].se] && !bad_bench(benches[0], mp(points[cur].x, points[cur].y), mp(points[new_id].x, points[new_id].y))) {
                        build_road_bench(cur, new_id, benches[0]);
                    } else {
                        build_road_bench(cur, new_id, benches[1]);
                    }
                }
            }
        }
    }
    //
}

#undef x
#undef y
int construct_roads(vector<int> x, vector<int> y) {
    // edge case
    if (x.size() == 1) {
        build({}, {}, {}, {});
        return 1;
    }
    // sample solution
    /*vector<int> u, v, a, b;
    u.push_back(0);
    v.push_back(1);
    a.push_back(x[0]+1);
    b.push_back(y[0]-1);
    build(u, v, a, b);*/
    n = x.size();
    if(!check_possibility(n, x, y)) {
        return 0;
    }
    X = x;
    Y = y;
    points.assign(n, fountain());
    for(int i = 0; i < n; i++) {
        points[i] = fountain(x[i], y[i], i);
        fountain_at[x[i]][y[i]] = i + 1;
    }
    solve();
    // build solution
    build(ans_u, ans_v, ans_a, ans_b);
    return 1;
}

/*
5
4 4
4 6
6 4
4 2
2 4
*/

Compilation message

parks.cpp: In function 'std::pair<int, int> get_bench_when_in_intersection(int, int)':
parks.cpp:138:1: warning: control reaches end of non-void function [-Wreturn-type]
  138 | }
      | ^

Subtask #1
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 1 ms 212 KB Output is correct
3 Correct 0 ms 212 KB Output is correct
4 Correct 0 ms 212 KB Output is correct
5 Correct 0 ms 212 KB Output is correct
6 Correct 0 ms 212 KB Output is correct
7 Correct 0 ms 212 KB Output is correct
8 Correct 0 ms 212 KB Output is correct
9 Correct 295 ms 40824 KB Output is correct
10 Correct 18 ms 3924 KB Output is correct
11 Correct 106 ms 21264 KB Output is correct
12 Correct 28 ms 6120 KB Output is correct
13 Correct 22 ms 7136 KB Output is correct
14 Correct 2 ms 340 KB Output is correct
15 Correct 2 ms 468 KB Output is correct
16 Correct 271 ms 40952 KB Output is correct

Subtask #2
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 1 ms 212 KB Output is correct
3 Correct 0 ms 212 KB Output is correct
4 Correct 0 ms 212 KB Output is correct
5 Correct 0 ms 212 KB Output is correct
6 Correct 0 ms 212 KB Output is correct
7 Correct 0 ms 212 KB Output is correct
8 Correct 0 ms 212 KB Output is correct
9 Correct 295 ms 40824 KB Output is correct
10 Correct 18 ms 3924 KB Output is correct
11 Correct 106 ms 21264 KB Output is correct
12 Correct 28 ms 6120 KB Output is correct
13 Correct 22 ms 7136 KB Output is correct
14 Correct 2 ms 340 KB Output is correct
15 Correct 2 ms 468 KB Output is correct
16 Correct 271 ms 40952 KB Output is correct
17 Correct 0 ms 212 KB Output is correct
18 Correct 1 ms 212 KB Output is correct
19 Correct 0 ms 212 KB Output is correct
20 Correct 0 ms 212 KB Output is correct
21 Correct 0 ms 212 KB Output is correct
22 Correct 0 ms 212 KB Output is correct
23 Correct 595 ms 72764 KB Output is correct
24 Correct 0 ms 212 KB Output is correct
25 Correct 3 ms 776 KB Output is correct
26 Correct 1 ms 596 KB Output is correct
27 Correct 2 ms 596 KB Output is correct
28 Correct 178 ms 26640 KB Output is correct
29 Correct 405 ms 47716 KB Output is correct
30 Correct 456 ms 61740 KB Output is correct
31 Correct 595 ms 72700 KB Output is correct
32 Correct 0 ms 212 KB Output is correct
33 Correct 0 ms 212 KB Output is correct
34 Correct 1 ms 212 KB Output is correct
35 Correct 1 ms 212 KB Output is correct
36 Correct 0 ms 212 KB Output is correct
37 Correct 0 ms 212 KB Output is correct
38 Correct 0 ms 212 KB Output is correct
39 Correct 0 ms 212 KB Output is correct
40 Correct 1 ms 212 KB Output is correct
41 Correct 1 ms 212 KB Output is correct
42 Correct 0 ms 212 KB Output is correct
43 Correct 2 ms 468 KB Output is correct
44 Correct 1 ms 468 KB Output is correct
45 Correct 385 ms 36392 KB Output is correct
46 Correct 598 ms 53148 KB Output is correct
47 Correct 574 ms 53372 KB Output is correct

Subtask #3
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 1 ms 212 KB Output is correct
3 Correct 0 ms 212 KB Output is correct
4 Correct 0 ms 212 KB Output is correct
5 Correct 0 ms 212 KB Output is correct
6 Correct 0 ms 212 KB Output is correct
7 Correct 0 ms 212 KB Output is correct
8 Correct 0 ms 212 KB Output is correct
9 Correct 295 ms 40824 KB Output is correct
10 Correct 18 ms 3924 KB Output is correct
11 Correct 106 ms 21264 KB Output is correct
12 Correct 28 ms 6120 KB Output is correct
13 Correct 22 ms 7136 KB Output is correct
14 Correct 2 ms 340 KB Output is correct
15 Correct 2 ms 468 KB Output is correct
16 Correct 271 ms 40952 KB Output is correct
17 Correct 0 ms 212 KB Output is correct
18 Correct 1 ms 212 KB Output is correct
19 Correct 0 ms 212 KB Output is correct
20 Correct 0 ms 212 KB Output is correct
21 Correct 0 ms 212 KB Output is correct
22 Correct 0 ms 212 KB Output is correct
23 Correct 595 ms 72764 KB Output is correct
24 Correct 0 ms 212 KB Output is correct
25 Correct 3 ms 776 KB Output is correct
26 Correct 1 ms 596 KB Output is correct
27 Correct 2 ms 596 KB Output is correct
28 Correct 178 ms 26640 KB Output is correct
29 Correct 405 ms 47716 KB Output is correct
30 Correct 456 ms 61740 KB Output is correct
31 Correct 595 ms 72700 KB Output is correct
32 Correct 0 ms 212 KB Output is correct
33 Correct 0 ms 212 KB Output is correct
34 Correct 1 ms 212 KB Output is correct
35 Correct 1 ms 212 KB Output is correct
36 Correct 0 ms 212 KB Output is correct
37 Correct 0 ms 212 KB Output is correct
38 Correct 0 ms 212 KB Output is correct
39 Correct 0 ms 212 KB Output is correct
40 Correct 1 ms 212 KB Output is correct
41 Correct 1 ms 212 KB Output is correct
42 Correct 0 ms 212 KB Output is correct
43 Correct 2 ms 468 KB Output is correct
44 Correct 1 ms 468 KB Output is correct
45 Correct 385 ms 36392 KB Output is correct
46 Correct 598 ms 53148 KB Output is correct
47 Correct 574 ms 53372 KB Output is correct
48 Correct 0 ms 212 KB Output is correct
49 Correct 0 ms 212 KB Output is correct
50 Correct 1 ms 212 KB Output is correct
51 Incorrect 0 ms 212 KB Tree @(5, 5) appears more than once: for edges on positions 1 and 4
52 Halted 0 ms 0 KB -

Subtask #4
0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 1 ms 212 KB Output is correct
3 Correct 0 ms 212 KB Output is correct
4 Correct 0 ms 212 KB Output is correct
5 Correct 0 ms 212 KB Output is correct
6 Correct 0 ms 212 KB Output is correct
7 Correct 0 ms 212 KB Output is correct
8 Correct 0 ms 212 KB Output is correct
9 Correct 295 ms 40824 KB Output is correct
10 Correct 18 ms 3924 KB Output is correct
11 Correct 106 ms 21264 KB Output is correct
12 Correct 28 ms 6120 KB Output is correct
13 Correct 22 ms 7136 KB Output is correct
14 Correct 2 ms 340 KB Output is correct
15 Correct 2 ms 468 KB Output is correct
16 Correct 271 ms 40952 KB Output is correct
17 Correct 0 ms 252 KB Output is correct
18 Correct 0 ms 212 KB Output is correct
19 Correct 0 ms 212 KB Output is correct
20 Execution timed out 3559 ms 185284 KB Time limit exceeded
21 Halted 0 ms 0 KB -

Subtask #5
0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 1 ms 212 KB Output is correct
3 Correct 0 ms 212 KB Output is correct
4 Correct 0 ms 212 KB Output is correct
5 Correct 0 ms 212 KB Output is correct
6 Correct 0 ms 212 KB Output is correct
7 Correct 0 ms 212 KB Output is correct
8 Correct 0 ms 212 KB Output is correct
9 Correct 295 ms 40824 KB Output is correct
10 Correct 18 ms 3924 KB Output is correct
11 Correct 106 ms 21264 KB Output is correct
12 Correct 28 ms 6120 KB Output is correct
13 Correct 22 ms 7136 KB Output is correct
14 Correct 2 ms 340 KB Output is correct
15 Correct 2 ms 468 KB Output is correct
16 Correct 271 ms 40952 KB Output is correct
17 Correct 951 ms 123544 KB Output is correct
18 Correct 1020 ms 123600 KB Output is correct
19 Execution timed out 3580 ms 136724 KB Time limit exceeded
20 Halted 0 ms 0 KB -

Subtask #6
0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 1 ms 212 KB Output is correct
3 Correct 0 ms 212 KB Output is correct
4 Correct 0 ms 212 KB Output is correct
5 Correct 0 ms 212 KB Output is correct
6 Correct 0 ms 212 KB Output is correct
7 Correct 0 ms 212 KB Output is correct
8 Correct 0 ms 212 KB Output is correct
9 Correct 295 ms 40824 KB Output is correct
10 Correct 18 ms 3924 KB Output is correct
11 Correct 106 ms 21264 KB Output is correct
12 Correct 28 ms 6120 KB Output is correct
13 Correct 22 ms 7136 KB Output is correct
14 Correct 2 ms 340 KB Output is correct
15 Correct 2 ms 468 KB Output is correct
16 Correct 271 ms 40952 KB Output is correct
17 Correct 0 ms 212 KB Output is correct
18 Correct 1 ms 212 KB Output is correct
19 Correct 0 ms 212 KB Output is correct
20 Correct 0 ms 212 KB Output is correct
21 Correct 0 ms 212 KB Output is correct
22 Correct 0 ms 212 KB Output is correct
23 Correct 595 ms 72764 KB Output is correct
24 Correct 0 ms 212 KB Output is correct
25 Correct 3 ms 776 KB Output is correct
26 Correct 1 ms 596 KB Output is correct
27 Correct 2 ms 596 KB Output is correct
28 Correct 178 ms 26640 KB Output is correct
29 Correct 405 ms 47716 KB Output is correct
30 Correct 456 ms 61740 KB Output is correct
31 Correct 595 ms 72700 KB Output is correct
32 Correct 0 ms 212 KB Output is correct
33 Correct 0 ms 212 KB Output is correct
34 Correct 1 ms 212 KB Output is correct
35 Correct 1 ms 212 KB Output is correct
36 Correct 0 ms 212 KB Output is correct
37 Correct 0 ms 212 KB Output is correct
38 Correct 0 ms 212 KB Output is correct
39 Correct 0 ms 212 KB Output is correct
40 Correct 1 ms 212 KB Output is correct
41 Correct 1 ms 212 KB Output is correct
42 Correct 0 ms 212 KB Output is correct
43 Correct 2 ms 468 KB Output is correct
44 Correct 1 ms 468 KB Output is correct
45 Correct 385 ms 36392 KB Output is correct
46 Correct 598 ms 53148 KB Output is correct
47 Correct 574 ms 53372 KB Output is correct
48 Correct 0 ms 212 KB Output is correct
49 Correct 0 ms 212 KB Output is correct
50 Correct 1 ms 212 KB Output is correct
51 Incorrect 0 ms 212 KB Tree @(5, 5) appears more than once: for edges on positions 1 and 4
52 Halted 0 ms 0 KB -