AGC049B求调

代码：

#include<bits/stdc++.h>
using namespace std;
#define int long long
int n,j=1,ans;
bool a[500005],b[500005];
signed main(){
	cin>>n;
	for(int i=1;i<=n;i++){
		char c;cin>>c;
		a[i]=c-'0';
	}
	for(int i=1;i<=n;i++){
		char c;cin>>c;
		b[i]=c-'0';
	}
	for(int i=1;i<=n;i++){
		if(a[i]==b[i])continue;
		j=max(i,j);
		while(a[j]==0&&j<=n)j++;
		if(j==n+1){
			cout<<-1;
			return 0;
		}
		cout<<i<<' '<<j<<endl;
		ans+=j-i;
		a[j]=0;
		j++;
	}
	cout<<ans;
	return 0;
}