oj.uz

답안 #1058628

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
1058628 2024-08-14T11:37:04 Z otarius Alternating Current (BOI18_alternating) C++17
0 / 100
 83 ms 15060 KB 
#include <bits/stdc++.h>
#include <bits/extc++.h>
using namespace __gnu_pbds;
using namespace std;

// #pragma GCC optimize("Ofast")
// #pragma GCC optimize ("unroll-loops")
// #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")

#define ff first
#define sc second
#define pb push_back
#define ll long long
#define pll pair<ll, ll>
#define pii pair<int, int>
#define ull unsigned long long
#define all(x) (x).begin(),(x).end()

// #define int long long
// #define int unsigned long long

// #define ordered_set(T) tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>
// #define ordered_multiset(T) tree<T, null_type, less_equal<T>, rb_tree_tag, tree_order_statistics_node_update>

void open_file(string filename) {
    freopen((filename + ".in").c_str(), "r", stdin);
    freopen((filename + ".out").c_str(), "w", stdout);
}

// const ll mod = 1e9 + 7;
// const ll mod = 998244353;

const ll inf = 1e9;
const ll biginf = 1e18;
const int maxN = 1e5 + 25;

int par[maxN];
vector<int> g[maxN];
void make_set() {
    for (int i = 0; i <= maxN; i++) par[i] = i;
}
int find_set(int v) {
    if (v == par[v])
        return v;
    return par[v] = find_set(par[v]);
}
void union_set(int x, int y) {
    x = find_set(x);
    y = find_set(y);
    if (x != y) par[y] = x;
}

struct segtree {
    int t[4 * maxN], lazy[4 * maxN], n;
    void init(int _n) {
        n = _n;
        for (int i = 0; i < 4 * maxN; i++)
            t[i] = lazy[i] = 0;
    }
    
    void prop(int v, int tl, int tr) {
        if (!lazy[v]) return;
        t[v] += lazy[v];
        if (tl != tr) {
            lazy[2 * v] += lazy[v];
            lazy[2 * v + 1] += lazy[v];
        } lazy[v] = 0;
    }
    
    void update(int v, int tl, int tr, int l, int r, int val) {
        prop(v, tl, tr);
        if (r < tl || tr < l) return;
        if (l <= tl && tr <= r) {
            lazy[v] += val;
            prop(v, tl, tr);
            return;
        } int tm = (tl + tr) / 2;
        update(2 * v, tl, tm, l, r, val);
        update(2 * v + 1, tm + 1, tr, l, r, val);
        t[v] = min(t[2 * v], t[2 * v + 1]);
    }
    
    int query(int v, int tl, int tr, int l, int r) {
        prop(v, tl, tr);
        if (l > r) return -inf;
        if (tl == l && tr == r)
            return t[v];
        int tm = (tl + tr) / 2;
        return min(query(2 * v, tl, tm, l, min(r, tm)),
                   query(2 * v + 1, tm + 1, tr, max(l, tm + 1), r));
    }
    
    void update(int l, int r, int val) {
        if (r > n) r -= n;
        if (l <= r) {
            update(1, 1, n, l, r, val);
        }
        else {
            update(1, 1, n, l, n, val);
            update(1, 1, n, 1, r, val);
        }
    }
    
    int eval() {
        return query(1, 1, n, 1, n);
    }
} seg[2];
bool check() {
    return (seg[0].eval() > 0 && seg[1].eval() > 0);
}

struct line {
    int x, y, id, cl, clr;
    line() {
        
    }
    line(int _x, int _y, int _id) {
        x = _x; y = _y; id = _id; cl = clr = -1;
    }
    bool operator<(const line &p) {
        return make_pair(x, -y) < make_pair(p.x, -p.y);
    }
} arr[maxN];
bool comp(line a, line b) {
    return a.id < b.id;
}

vector<line> good;
int n, m, mx, mxi, cld[maxN];
void elim() {
    deque<line> dq;
    sort(arr + 1, arr + m + 1);
    for (int i = 1; i <= n; i++) {
        if (dq.empty() || dq.back().y < arr[i].y) dq.push_back(arr[i]);
        else cld[arr[i].id] = dq.back().id;
    } while (dq.size() && dq.front().y <= mx) {
        cld[dq.front().id] = mxi; dq.pop_front();
    } for (line x : dq) good.pb(x);
    for (int i = 1; i <= m; i++)
        if (cld[arr[i].id]) arr[i].cl = cld[arr[i].id];
    make_set();
    for (int i = 1; i <= m; i++)
        if (arr[i].cl != -1) union_set(arr[i].cl, arr[i].id);
    for (int i = 1; i <= m; i++) {
        if (arr[i].cl != -1) {
            arr[i].cl = find_set(arr[i].id);
            g[arr[i].cl].pb(arr[i].id);
        } else g[arr[i].id].pb(arr[i].id);
    }
}
void even() {
    for (int i = 0; i < good.size(); i++)
        arr[good[i].id].clr = i % 2;
    for (int i = 1; i <= m; i++)
        if (arr[i].clr == -1) arr[i].clr = (arr[arr[i].cl].clr ^ 1);
    for (int i = 1; i <= m; i++) {
        seg[arr[i].clr].update(arr[i].x, arr[i].y, 1);
    }
    if (check()) {
        for (int i = 1; i <= m; i++)
            cout << arr[i].clr;
    } else {
        cout << "impossible";
    } exit(0);
}
void odd() {
    for (int i = 0; i < good.size(); i++)
        arr[good[i].id].clr = i % 2;
    for (int i = 1; i <= m; i++)
        if (arr[i].clr == -1) arr[i].clr = (arr[arr[i].cl].clr ^ 1);
    for (int i = 1; i <= m; i++)
        seg[arr[i].clr].update(arr[i].x, arr[i].y, 1);
    if (check()) {
        for (int i = 1; i <= m; i++)
            cout << arr[i].clr;
        exit(0);
    } for (int i = 0; i < good.size(); i++) {
        for (int j : g[good[i].id]) {
            seg[arr[j].clr].update(arr[j].x, arr[j].y, -1);
            arr[j].clr ^= 1;
            seg[arr[j].clr].update(arr[j].x, arr[j].y, 1);
        } if (check()) {
            for (int j = 1; j <= m; j++)
                cout << arr[j].clr;
            exit(0);
        }
    } cout << "impossible";
    exit(0);
}
void solve() {
    cin >> n >> m;
    seg[0].init(n); seg[1].init(n);
    for (int i = 1; i <= m; i++) {
        int l, r; cin >> l >> r;
        if (l > r) {
            if (mx < r) {
                mx = r; mxi = i;
            } r += n;
        } arr[i] = {l, r, i};
    } elim();
    sort(arr + 1, arr + m + 1, comp);
    if (good.size() % 2 == 0) even();
    else odd();
}
int32_t main() { 
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr); cout.tie(nullptr);
    
    int t = 1;
    // cin >> t;
    while (t--) {
        solve();
        cout << '\n';
    }
    return 0;
}

Compilation message

alternating.cpp: In function 'void even()':
alternating.cpp:152:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<line>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  152 |     for (int i = 0; i < good.size(); i++)
      |                     ~~^~~~~~~~~~~~~
alternating.cpp: In function 'void odd()':
alternating.cpp:167:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<line>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  167 |     for (int i = 0; i < good.size(); i++)
      |                     ~~^~~~~~~~~~~~~
alternating.cpp:177:25: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<line>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  177 |     } for (int i = 0; i < good.size(); i++) {
      |                       ~~^~~~~~~~~~~~~
alternating.cpp: In function 'void open_file(std::string)':
alternating.cpp:26:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   26 |     freopen((filename + ".in").c_str(), "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
alternating.cpp:27:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   27 |     freopen((filename + ".out").c_str(), "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
alternating.cpp: In function 'void make_set()':
alternating.cpp:40:44: warning: iteration 100025 invokes undefined behavior [-Waggressive-loop-optimizations]
   40 |     for (int i = 0; i <= maxN; i++) par[i] = i;
      |                                     ~~~~~~~^~~
alternating.cpp:40:23: note: within this loop
   40 |     for (int i = 0; i <= maxN; i++) par[i] = i;
      |                     ~~^~~~~~~

Subtask #1
0 / 13.0

# 결과 실행 시간 메모리 Grader output
1 Correct 2 ms 11612 KB Output is correct
2 Correct 1 ms 11612 KB Output is correct
3 Correct 1 ms 11612 KB Output is correct
4 Correct 1 ms 11612 KB Output is correct
5 Correct 1 ms 11612 KB Output is correct
6 Correct 1 ms 11612 KB Output is correct
7 Correct 2 ms 11612 KB Output is correct
8 Correct 2 ms 11612 KB Output is correct
9 Correct 1 ms 11612 KB Output is correct
10 Correct 1 ms 11612 KB Output is correct
11 Correct 1 ms 11524 KB Output is correct
12 Correct 1 ms 11612 KB Output is correct
13 Correct 1 ms 11612 KB Output is correct
14 Correct 1 ms 11612 KB Output is correct
15 Correct 1 ms 11612 KB Output is correct
16 Correct 1 ms 11612 KB Output is correct
17 Correct 2 ms 11608 KB Output is correct
18 Correct 1 ms 11612 KB Output is correct
19 Correct 2 ms 11612 KB Output is correct
20 Correct 1 ms 11612 KB Output is correct
21 Correct 1 ms 11516 KB Output is correct
22 Correct 1 ms 11612 KB Output is correct
23 Correct 2 ms 11612 KB Output is correct
24 Correct 2 ms 11612 KB Output is correct
25 Correct 1 ms 11612 KB Output is correct
26 Correct 1 ms 11612 KB Output is correct
27 Correct 1 ms 11612 KB Output is correct
28 Correct 1 ms 11612 KB Output is correct
29 Correct 2 ms 11612 KB Output is correct
30 Correct 2 ms 11612 KB Output is correct
31 Correct 2 ms 11612 KB Output is correct
32 Correct 2 ms 11612 KB Output is correct
33 Correct 1 ms 11612 KB Output is correct
34 Correct 1 ms 11612 KB Output is correct
35 Correct 1 ms 11608 KB Output is correct
36 Correct 1 ms 11612 KB Output is correct
37 Incorrect 1 ms 11612 KB 'impossible' claimed, but there is a solution
38 Halted 0 ms 0 KB -

Subtask #2
0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Correct 2 ms 11612 KB Output is correct
2 Correct 1 ms 11612 KB Output is correct
3 Correct 1 ms 11612 KB Output is correct
4 Correct 1 ms 11612 KB Output is correct
5 Correct 1 ms 11612 KB Output is correct
6 Correct 1 ms 11612 KB Output is correct
7 Correct 2 ms 11612 KB Output is correct
8 Correct 2 ms 11612 KB Output is correct
9 Correct 1 ms 11612 KB Output is correct
10 Correct 1 ms 11612 KB Output is correct
11 Correct 1 ms 11524 KB Output is correct
12 Correct 1 ms 11612 KB Output is correct
13 Correct 1 ms 11612 KB Output is correct
14 Correct 1 ms 11612 KB Output is correct
15 Correct 1 ms 11612 KB Output is correct
16 Correct 1 ms 11612 KB Output is correct
17 Correct 2 ms 11608 KB Output is correct
18 Correct 1 ms 11612 KB Output is correct
19 Correct 2 ms 11612 KB Output is correct
20 Correct 1 ms 11612 KB Output is correct
21 Correct 1 ms 11516 KB Output is correct
22 Correct 1 ms 11612 KB Output is correct
23 Correct 2 ms 11612 KB Output is correct
24 Correct 2 ms 11612 KB Output is correct
25 Correct 1 ms 11612 KB Output is correct
26 Correct 1 ms 11612 KB Output is correct
27 Correct 1 ms 11612 KB Output is correct
28 Correct 1 ms 11612 KB Output is correct
29 Correct 2 ms 11612 KB Output is correct
30 Correct 2 ms 11612 KB Output is correct
31 Correct 2 ms 11612 KB Output is correct
32 Correct 2 ms 11612 KB Output is correct
33 Correct 1 ms 11612 KB Output is correct
34 Correct 1 ms 11612 KB Output is correct
35 Correct 1 ms 11608 KB Output is correct
36 Correct 1 ms 11612 KB Output is correct
37 Incorrect 1 ms 11612 KB 'impossible' claimed, but there is a solution
38 Halted 0 ms 0 KB -

Subtask #3
0 / 22.0

# 결과 실행 시간 메모리 Grader output
1 Correct 2 ms 11612 KB Output is correct
2 Correct 1 ms 11612 KB Output is correct
3 Correct 1 ms 11612 KB Output is correct
4 Correct 1 ms 11612 KB Output is correct
5 Correct 1 ms 11612 KB Output is correct
6 Correct 1 ms 11612 KB Output is correct
7 Correct 2 ms 11612 KB Output is correct
8 Correct 2 ms 11612 KB Output is correct
9 Correct 1 ms 11612 KB Output is correct
10 Correct 1 ms 11612 KB Output is correct
11 Correct 1 ms 11524 KB Output is correct
12 Correct 1 ms 11612 KB Output is correct
13 Correct 1 ms 11612 KB Output is correct
14 Correct 1 ms 11612 KB Output is correct
15 Correct 1 ms 11612 KB Output is correct
16 Correct 1 ms 11612 KB Output is correct
17 Correct 2 ms 11608 KB Output is correct
18 Correct 1 ms 11612 KB Output is correct
19 Correct 2 ms 11612 KB Output is correct
20 Correct 1 ms 11612 KB Output is correct
21 Correct 1 ms 11516 KB Output is correct
22 Correct 1 ms 11612 KB Output is correct
23 Correct 2 ms 11612 KB Output is correct
24 Correct 2 ms 11612 KB Output is correct
25 Correct 1 ms 11612 KB Output is correct
26 Correct 1 ms 11612 KB Output is correct
27 Correct 1 ms 11612 KB Output is correct
28 Correct 1 ms 11612 KB Output is correct
29 Correct 2 ms 11612 KB Output is correct
30 Correct 2 ms 11612 KB Output is correct
31 Correct 2 ms 11612 KB Output is correct
32 Correct 2 ms 11612 KB Output is correct
33 Correct 1 ms 11612 KB Output is correct
34 Correct 1 ms 11612 KB Output is correct
35 Correct 1 ms 11608 KB Output is correct
36 Correct 1 ms 11612 KB Output is correct
37 Incorrect 1 ms 11612 KB 'impossible' claimed, but there is a solution
38 Halted 0 ms 0 KB -

Subtask #4
0 / 19.0

# 결과 실행 시간 메모리 Grader output
1 Correct 20 ms 12252 KB Output is correct
2 Correct 2 ms 11608 KB Output is correct
3 Correct 43 ms 12120 KB Output is correct
4 Correct 21 ms 12204 KB Output is correct
5 Correct 51 ms 14696 KB Output is correct
6 Correct 83 ms 13904 KB Output is correct
7 Correct 45 ms 12956 KB Output is correct
8 Correct 3 ms 11608 KB Output is correct
9 Correct 2 ms 11612 KB Output is correct
10 Correct 56 ms 14716 KB Output is correct
11 Correct 41 ms 13400 KB Output is correct
12 Correct 43 ms 12252 KB Output is correct
13 Correct 2 ms 11608 KB Output is correct
14 Correct 2 ms 11612 KB Output is correct
15 Correct 52 ms 12460 KB Output is correct
16 Correct 46 ms 15060 KB Output is correct
17 Correct 70 ms 12380 KB Output is correct
18 Incorrect 57 ms 14680 KB 'impossible' claimed, but there is a solution
19 Halted 0 ms 0 KB -

Subtask #5
0 / 26.0

# 결과 실행 시간 메모리 Grader output
1 Correct 2 ms 11612 KB Output is correct
2 Correct 1 ms 11612 KB Output is correct
3 Correct 1 ms 11612 KB Output is correct
4 Correct 1 ms 11612 KB Output is correct
5 Correct 1 ms 11612 KB Output is correct
6 Correct 1 ms 11612 KB Output is correct
7 Correct 2 ms 11612 KB Output is correct
8 Correct 2 ms 11612 KB Output is correct
9 Correct 1 ms 11612 KB Output is correct
10 Correct 1 ms 11612 KB Output is correct
11 Correct 1 ms 11524 KB Output is correct
12 Correct 1 ms 11612 KB Output is correct
13 Correct 1 ms 11612 KB Output is correct
14 Correct 1 ms 11612 KB Output is correct
15 Correct 1 ms 11612 KB Output is correct
16 Correct 1 ms 11612 KB Output is correct
17 Correct 2 ms 11608 KB Output is correct
18 Correct 1 ms 11612 KB Output is correct
19 Correct 2 ms 11612 KB Output is correct
20 Correct 1 ms 11612 KB Output is correct
21 Correct 1 ms 11516 KB Output is correct
22 Correct 1 ms 11612 KB Output is correct
23 Correct 2 ms 11612 KB Output is correct
24 Correct 2 ms 11612 KB Output is correct
25 Correct 1 ms 11612 KB Output is correct
26 Correct 1 ms 11612 KB Output is correct
27 Correct 1 ms 11612 KB Output is correct
28 Correct 1 ms 11612 KB Output is correct
29 Correct 2 ms 11612 KB Output is correct
30 Correct 2 ms 11612 KB Output is correct
31 Correct 2 ms 11612 KB Output is correct
32 Correct 2 ms 11612 KB Output is correct
33 Correct 1 ms 11612 KB Output is correct
34 Correct 1 ms 11612 KB Output is correct
35 Correct 1 ms 11608 KB Output is correct
36 Correct 1 ms 11612 KB Output is correct
37 Incorrect 1 ms 11612 KB 'impossible' claimed, but there is a solution
38 Halted 0 ms 0 KB -