Submission #3457521

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Source Code Expand

#include<iostream>
using namespace std;
int a[300010],b[300010],n,m,sum;
bool vis[100010],stk[100010],top;
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++) {if(b[j])break;b[j]=i;}
		for(int j=r;j>=l;j--) {if(b[j])break;b[j]=i;}
	}
	for(int i=1;i<=n;i++){
		a[i]+=a[i-1];
	    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