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Submission #941292

# Submission time Handle Problem Language Result Execution time Memory
941292 2024-03-08T13:08:48 Z phoenix0423 Alternating Current (BOI18_alternating) C++17
32 / 100
 73 ms 12992 KB 
#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> pll;
#define fastio ios::sync_with_stdio(false), cin.tie(0)
#define pb push_back
#define eb emplace_back
#define f first
#define s second
#define int long long
#define lowbit(x) x&-x
const int maxn = 1e5 + 5;
const int INF = 1e18;
int n, m;

struct seg{
    int l, r, id;
    seg(){}
    seg(int _l, int _r, int _id) : l(_l), r(_r), id(_id){
        if(r < l) r += n;
    }
    bool operator < (const seg& other) const{
        if(l != other.l) return l < other.l;
        return r < other.r;
    }
};

class comp{
    public:
        bool operator ()(seg a, seg b){
            if(a.r != b.r) return a.r < b.r;
            else return a.l < b.l;
        }
};

int st[maxn * 4], tag[maxn * 4];

void cast(int val, int v){
    st[v] += val, tag[v] += val;
}

void push(int v){
    if(tag[v]){
        cast(tag[v], v * 2);
        cast(tag[v], v * 2 + 1);
        tag[v] = 0;
    }
}
void upd(int l, int r, int val, int v = 1, int L = 0, int R = n - 1){
    if(l > R || r < L) return;
    if(l <= L && r >= R){
        st[v] += val, tag[v] += val;
        return;
    }
    push(v);
    int m = (L + R) / 2;
    upd(l, r, val, v * 2, L, m);
    upd(l, r, val, v * 2 + 1, m + 1, R);
    st[v] = min(st[v * 2], st[v * 2 + 1]);
}
int qry(int l, int r, int v = 1, int L = 0, int R = n - 1){
    if(l > R || r < L) return INF;
    if(l <= L && r >= R) return st[v];
    push(v);
    int m = (L + R) / 2;
    return min(qry(l, r, v * 2, L, m), qry(l, r, v * 2 + 1, m + 1, R));
}
void insert(int l, int r, int val){
    l %= n, r %= n;
    if(l <= r) upd(l, r, val);
    else upd(l, n - 1, val), upd(0, r, val);
}

bool ck(seg a){
    a.l %= n, a.r %= n;
    if(a.l <= a.r) return qry(a.l, a.r) >= 2;
    else return min(qry(a.l, n - 1), qry(0, a.r)) >= 2;
}
int getlen(int a, int b){
    return (b - a + n) % n + 1;
}
signed main(void){
    fastio;
    cin>>n>>m;
    vector<seg> e;
    int mx = 0;
    int st = 0;
    for(int i = 0; i < m; i++){
        int a, b;
        cin>>a>>b;
        a--, b--;
        a += n, b += n;
        if(getlen(a, b) > mx) mx = getlen(a, b), st = a;
        insert(a, b, 1);
        e.pb(seg(a, b, i));
    }
    if(qry(0, n - 1) < 2){
        cout<<"impossible\n";
        return 0;
    }
    // for(int i = 0; i < m; i++){
    //     if(e[i].l < st) e[i].l += n;
    //     if(e[i].r < e[i].l) e[i].r += n;
    //     cout<<e[i].l<<" "<<e[i].r<<"\n";
    // }
    sort(e.begin(), e.end());
    int r = e[0].l - 1;
    vector<int> ans(m);
    int id = 0;
    priority_queue<seg, vector<seg>, comp> q;
    int dist = 0;
    while(true){
        // cout<<"r : "<<r<<"\n";
        while(id < m && e[id].l <= r + 1){
            // cout<<"push : "<<e[id].l<<" "<<e[id].r<<" "<<e[id].id<<"\n";
            q.push(e[id]);
            id++;
        }
        while(true){
            if(q.empty()){
                cout<<"impossible\n";
                return 0;
            }
            seg cur = q.top(); q.pop();
            if(!ck(cur)) continue;
            if(cur.r <= r) continue;
            // cout<<"use : "<<cur.l<<" "<<cur.r<<" "<<cur.id<<"\n";
            insert(cur.l, cur.r, -1);
            ans[cur.id] = 1;
            dist += cur.r - r;
            r = cur.r;
            break;
        }
        // cout<<dist<<"\n";
        if(dist >= n) break;
    }
    for(auto x : ans) cout<<x;
    cout<<"\n";
}

Compilation message

alternating.cpp: In function 'int main()':
alternating.cpp:87:9: warning: variable 'st' set but not used [-Wunused-but-set-variable]
   87 |     int st = 0;
      |         ^~

Subtask #1
13.0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2392 KB Output is correct
2 Correct 0 ms 2396 KB Output is correct
3 Correct 0 ms 2396 KB Output is correct
4 Correct 0 ms 2396 KB Output is correct
5 Correct 1 ms 2392 KB Output is correct
6 Correct 1 ms 2396 KB Output is correct
7 Correct 1 ms 2396 KB Output is correct
8 Correct 1 ms 2396 KB Output is correct
9 Correct 1 ms 2396 KB Output is correct
10 Correct 1 ms 2396 KB Output is correct
11 Correct 1 ms 2396 KB Output is correct
12 Correct 1 ms 2392 KB Output is correct
13 Correct 1 ms 2392 KB Output is correct
14 Correct 0 ms 2396 KB Output is correct
15 Correct 1 ms 2396 KB Output is correct
16 Correct 1 ms 2396 KB Output is correct
17 Correct 1 ms 2396 KB Output is correct
18 Correct 1 ms 2396 KB Output is correct
19 Correct 1 ms 2396 KB Output is correct
20 Correct 1 ms 2396 KB Output is correct
21 Correct 1 ms 2396 KB Output is correct
22 Correct 1 ms 2396 KB Output is correct
23 Correct 1 ms 2396 KB Output is correct
24 Correct 1 ms 2396 KB Output is correct
25 Correct 0 ms 2396 KB Output is correct
26 Correct 1 ms 2392 KB Output is correct
27 Correct 1 ms 2396 KB Output is correct
28 Correct 1 ms 2396 KB Output is correct
29 Correct 1 ms 2396 KB Output is correct
30 Correct 1 ms 2396 KB Output is correct
31 Correct 1 ms 2392 KB Output is correct
32 Correct 1 ms 2396 KB Output is correct
33 Correct 0 ms 2396 KB Output is correct
34 Correct 1 ms 2516 KB Output is correct
35 Correct 1 ms 2396 KB Output is correct
36 Correct 1 ms 2396 KB Output is correct
37 Correct 1 ms 2396 KB Output is correct
38 Correct 1 ms 2396 KB Output is correct
39 Correct 0 ms 2396 KB Output is correct
40 Correct 0 ms 2396 KB Output is correct

Subtask #2
0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2392 KB Output is correct
2 Correct 0 ms 2396 KB Output is correct
3 Correct 0 ms 2396 KB Output is correct
4 Correct 0 ms 2396 KB Output is correct
5 Correct 1 ms 2392 KB Output is correct
6 Correct 1 ms 2396 KB Output is correct
7 Correct 1 ms 2396 KB Output is correct
8 Correct 1 ms 2396 KB Output is correct
9 Correct 1 ms 2396 KB Output is correct
10 Correct 1 ms 2396 KB Output is correct
11 Correct 1 ms 2396 KB Output is correct
12 Correct 1 ms 2392 KB Output is correct
13 Correct 1 ms 2392 KB Output is correct
14 Correct 0 ms 2396 KB Output is correct
15 Correct 1 ms 2396 KB Output is correct
16 Correct 1 ms 2396 KB Output is correct
17 Correct 1 ms 2396 KB Output is correct
18 Correct 1 ms 2396 KB Output is correct
19 Correct 1 ms 2396 KB Output is correct
20 Correct 1 ms 2396 KB Output is correct
21 Correct 1 ms 2396 KB Output is correct
22 Correct 1 ms 2396 KB Output is correct
23 Correct 1 ms 2396 KB Output is correct
24 Correct 1 ms 2396 KB Output is correct
25 Correct 0 ms 2396 KB Output is correct
26 Correct 1 ms 2392 KB Output is correct
27 Correct 1 ms 2396 KB Output is correct
28 Correct 1 ms 2396 KB Output is correct
29 Correct 1 ms 2396 KB Output is correct
30 Correct 1 ms 2396 KB Output is correct
31 Correct 1 ms 2392 KB Output is correct
32 Correct 1 ms 2396 KB Output is correct
33 Correct 0 ms 2396 KB Output is correct
34 Correct 1 ms 2516 KB Output is correct
35 Correct 1 ms 2396 KB Output is correct
36 Correct 1 ms 2396 KB Output is correct
37 Correct 1 ms 2396 KB Output is correct
38 Correct 1 ms 2396 KB Output is correct
39 Correct 0 ms 2396 KB Output is correct
40 Correct 0 ms 2396 KB Output is correct
41 Correct 1 ms 2396 KB Output is correct
42 Incorrect 1 ms 2396 KB 'impossible' claimed, but there is a solution
43 Halted 0 ms 0 KB -

Subtask #3
0 / 22.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2392 KB Output is correct
2 Correct 0 ms 2396 KB Output is correct
3 Correct 0 ms 2396 KB Output is correct
4 Correct 0 ms 2396 KB Output is correct
5 Correct 1 ms 2392 KB Output is correct
6 Correct 1 ms 2396 KB Output is correct
7 Correct 1 ms 2396 KB Output is correct
8 Correct 1 ms 2396 KB Output is correct
9 Correct 1 ms 2396 KB Output is correct
10 Correct 1 ms 2396 KB Output is correct
11 Correct 1 ms 2396 KB Output is correct
12 Correct 1 ms 2392 KB Output is correct
13 Correct 1 ms 2392 KB Output is correct
14 Correct 0 ms 2396 KB Output is correct
15 Correct 1 ms 2396 KB Output is correct
16 Correct 1 ms 2396 KB Output is correct
17 Correct 1 ms 2396 KB Output is correct
18 Correct 1 ms 2396 KB Output is correct
19 Correct 1 ms 2396 KB Output is correct
20 Correct 1 ms 2396 KB Output is correct
21 Correct 1 ms 2396 KB Output is correct
22 Correct 1 ms 2396 KB Output is correct
23 Correct 1 ms 2396 KB Output is correct
24 Correct 1 ms 2396 KB Output is correct
25 Correct 0 ms 2396 KB Output is correct
26 Correct 1 ms 2392 KB Output is correct
27 Correct 1 ms 2396 KB Output is correct
28 Correct 1 ms 2396 KB Output is correct
29 Correct 1 ms 2396 KB Output is correct
30 Correct 1 ms 2396 KB Output is correct
31 Correct 1 ms 2392 KB Output is correct
32 Correct 1 ms 2396 KB Output is correct
33 Correct 0 ms 2396 KB Output is correct
34 Correct 1 ms 2516 KB Output is correct
35 Correct 1 ms 2396 KB Output is correct
36 Correct 1 ms 2396 KB Output is correct
37 Correct 1 ms 2396 KB Output is correct
38 Correct 1 ms 2396 KB Output is correct
39 Correct 0 ms 2396 KB Output is correct
40 Correct 0 ms 2396 KB Output is correct
41 Correct 1 ms 2396 KB Output is correct
42 Incorrect 1 ms 2396 KB 'impossible' claimed, but there is a solution
43 Halted 0 ms 0 KB -

Subtask #4
19.0 / 19.0

# Verdict Execution time Memory Grader output
1 Correct 21 ms 11468 KB Output is correct
2 Correct 1 ms 2396 KB Output is correct
3 Correct 24 ms 6868 KB Output is correct
4 Correct 24 ms 7120 KB Output is correct
5 Correct 64 ms 11564 KB Output is correct
6 Correct 40 ms 8388 KB Output is correct
7 Correct 55 ms 12736 KB Output is correct
8 Correct 4 ms 5464 KB Output is correct
9 Correct 2 ms 5212 KB Output is correct
10 Correct 67 ms 11660 KB Output is correct
11 Correct 49 ms 11028 KB Output is correct
12 Correct 43 ms 9936 KB Output is correct
13 Correct 1 ms 2648 KB Output is correct
14 Correct 1 ms 2648 KB Output is correct
15 Correct 47 ms 8656 KB Output is correct
16 Correct 22 ms 6596 KB Output is correct
17 Correct 73 ms 12992 KB Output is correct
18 Correct 55 ms 10176 KB Output is correct
19 Correct 5 ms 5724 KB Output is correct
20 Correct 63 ms 9220 KB Output is correct

Subtask #5
0 / 26.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2392 KB Output is correct
2 Correct 0 ms 2396 KB Output is correct
3 Correct 0 ms 2396 KB Output is correct
4 Correct 0 ms 2396 KB Output is correct
5 Correct 1 ms 2392 KB Output is correct
6 Correct 1 ms 2396 KB Output is correct
7 Correct 1 ms 2396 KB Output is correct
8 Correct 1 ms 2396 KB Output is correct
9 Correct 1 ms 2396 KB Output is correct
10 Correct 1 ms 2396 KB Output is correct
11 Correct 1 ms 2396 KB Output is correct
12 Correct 1 ms 2392 KB Output is correct
13 Correct 1 ms 2392 KB Output is correct
14 Correct 0 ms 2396 KB Output is correct
15 Correct 1 ms 2396 KB Output is correct
16 Correct 1 ms 2396 KB Output is correct
17 Correct 1 ms 2396 KB Output is correct
18 Correct 1 ms 2396 KB Output is correct
19 Correct 1 ms 2396 KB Output is correct
20 Correct 1 ms 2396 KB Output is correct
21 Correct 1 ms 2396 KB Output is correct
22 Correct 1 ms 2396 KB Output is correct
23 Correct 1 ms 2396 KB Output is correct
24 Correct 1 ms 2396 KB Output is correct
25 Correct 0 ms 2396 KB Output is correct
26 Correct 1 ms 2392 KB Output is correct
27 Correct 1 ms 2396 KB Output is correct
28 Correct 1 ms 2396 KB Output is correct
29 Correct 1 ms 2396 KB Output is correct
30 Correct 1 ms 2396 KB Output is correct
31 Correct 1 ms 2392 KB Output is correct
32 Correct 1 ms 2396 KB Output is correct
33 Correct 0 ms 2396 KB Output is correct
34 Correct 1 ms 2516 KB Output is correct
35 Correct 1 ms 2396 KB Output is correct
36 Correct 1 ms 2396 KB Output is correct
37 Correct 1 ms 2396 KB Output is correct
38 Correct 1 ms 2396 KB Output is correct
39 Correct 0 ms 2396 KB Output is correct
40 Correct 0 ms 2396 KB Output is correct
41 Correct 1 ms 2396 KB Output is correct
42 Incorrect 1 ms 2396 KB 'impossible' claimed, but there is a solution
43 Halted 0 ms 0 KB -