Submission #3457819

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Source Code Expand

#pragma GCC optimize(2)
#include<iostream>
using namespace std;
int a[300010],b[300010],n,m,sum;
bool vis[100010];
int main(){
    int l,r;
    cin>>n>>m;
    for(int i=1;i<=m;i++){
        cin>>l>>r;
        if(l>r) swap(l,r);
        a[l]++;a[r+1]--;
        for(int j=l;j<=r;j++) {b[j]=i;}
    }
    for(int i=1;i<=n;i++) a[i]+=a[i-1];
    for(int i=1;i<=n;i++) if(a[i]==1) {sum+=(!vis[b[i]]);vis[b[i]]=1;}
    cout<<m-sum<<endl;
    for(int i=1;i<=m;i++) if(!vis[i]) cout<<i<<endl;
    return 0;
}

Submission Info

Judge Result