oj.uz

Submission #63270

# Submission time Handle Problem Language Result Execution time Memory
63270 2018-08-01T08:16:45 Z 노영훈(#1832) Alternating Current (BOI18_alternating) C++11
19 / 100
 81 ms 3604 KB 
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
const int MX=100010, inf=2e9;

int n, m;
struct line{
    int s, e, ans=-1, idx;
    void scan(){
        cin>>s>>e;
    }
    bool operator < (const line &l) const {
        return s<l.s || (s==l.s && e>l.e);
    }
} L[MX];

bool solve(){
    bool done[MX][2]={};


    priority_queue<pii> Q;
    for(int i=1, frt=0; i<=n; i++){
        while(frt<m && L[frt+1].s<=i) frt++, Q.push({L[frt].e, frt});
        for(int j=0; j<=1; j++){
            if(done[i][j]) continue;
            while(!Q.empty() && Q.top().first<i) Q.pop();
            if(Q.empty()) return false;
            int e,idx; tie(e,idx)=Q.top(); Q.pop();
            for(int x=i; x<=e; x++) done[x][j]=true;
            L[idx].ans=j;
        }
    }
    return true;
}

void solve3(){
    deque<int> A[MX];
    for(int i=1; i<=m; i++) A[L[i].s].push_back(i);
    deque<int> used;
    priority_queue<pii> Q;
    for(int i=1, r=0; i<=n; i++){
        for(int idx:A[i]) Q.push({L[idx].e + (i<=L[idx].e ? 0 : n), idx});
        if(i<=r) continue;
        pii now=Q.top(); Q.pop();
        r=now.first; used.push_back(now.second);
    }
    int cnt[MX]={};
    for(int x:used) for(int ii=L[x].s; ii<=L[x].e + (L[x].s<=L[x].e ? 0 : n); ii++)
        cnt[(ii-1)%n+1]++;
    bool out=false;
    for(int i=1; i<=n; i++) if(cnt[i]>=3) out=true;
    if(out) used.pop_front();
    for(int x:used) L[x].ans=1;
}

void show(){
    sort(L+1, L+m+1, [](line &a, line &b){ return a.idx<b.idx; });
    for(int i=1; i<=m; i++) cout<<max(0,L[i].ans);
    cout<<'\n';
}

bool is3(){
    int cnt[100010]={};
    for(int i=1; i<=m; i++){
        int s=L[i].s, e=L[i].e;
        if(s<=e){
            cnt[s]++, cnt[e+1]--;
        }
        else{
            cnt[1]++, cnt[s+1]--;
            cnt[e]++, cnt[n+1]--;
        }
    }
    for(int i=1, now=0; i<=n; i++){
        now+=cnt[i];
        if(now<3) return false;
    }
    return false;
}

int main(){
    ios::sync_with_stdio(0); cin.tie(0);
    cin>>n>>m;
    for(int i=1; i<=m; i++) L[i].scan(), L[i].idx=i;
    sort(L+1, L+m+1);

    if(is3()) solve3(), show();

    if(!solve()){ cout<<"impossible\n"; return 0; }
    show();
    return 0;
}

Subtask #1
0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 2040 KB Output is correct
2 Correct 5 ms 2148 KB Output is correct
3 Incorrect 5 ms 2148 KB 'impossible' claimed, but there is a solution
4 Halted 0 ms 0 KB -

Subtask #2
0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 2040 KB Output is correct
2 Correct 5 ms 2148 KB Output is correct
3 Incorrect 5 ms 2148 KB 'impossible' claimed, but there is a solution
4 Halted 0 ms 0 KB -

Subtask #3
0 / 22.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 2040 KB Output is correct
2 Correct 5 ms 2148 KB Output is correct
3 Incorrect 5 ms 2148 KB 'impossible' claimed, but there is a solution
4 Halted 0 ms 0 KB -

Subtask #4
19.0 / 19.0

# Verdict Execution time Memory Grader output
1 Correct 57 ms 3352 KB Output is correct
2 Correct 7 ms 3352 KB Output is correct
3 Correct 19 ms 3352 KB Output is correct
4 Correct 25 ms 3352 KB Output is correct
5 Correct 71 ms 3352 KB Output is correct
6 Correct 47 ms 3352 KB Output is correct
7 Correct 62 ms 3352 KB Output is correct
8 Correct 7 ms 3352 KB Output is correct
9 Correct 6 ms 3352 KB Output is correct
10 Correct 62 ms 3352 KB Output is correct
11 Correct 57 ms 3352 KB Output is correct
12 Correct 63 ms 3352 KB Output is correct
13 Correct 4 ms 3352 KB Output is correct
14 Correct 6 ms 3352 KB Output is correct
15 Correct 72 ms 3600 KB Output is correct
16 Correct 30 ms 3600 KB Output is correct
17 Correct 81 ms 3600 KB Output is correct
18 Correct 63 ms 3604 KB Output is correct
19 Correct 7 ms 3604 KB Output is correct
20 Correct 64 ms 3604 KB Output is correct

Subtask #5
0 / 26.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 2040 KB Output is correct
2 Correct 5 ms 2148 KB Output is correct
3 Incorrect 5 ms 2148 KB 'impossible' claimed, but there is a solution
4 Halted 0 ms 0 KB -