有没有大佬帮我查查错（悬赏一关）

#include<bits/stdc++.h>
using namespace std;
int n;
int a[200005];
int vis[200005];
int sum=0;
int ans1[200005];
int ans2[200005];
string s;
struct node
{
    int qian;
    int hou;
    int cha;
};
struct jiedian
{
    int before;
    int next;
}lianbiao[200005];
priority_queue<node> q;
bool operator<(node a,node b)
{
	if(a.cha==b.cha)
        	return a.qian>b.qian;
	else return a.cha>b.cha;
}
void qpush(int a,int b,int c)
{
    node d;
    d.qian=a;
    d.hou=b;
    d.cha=c;
    q.push(d);
}
int main()
{
    cin>>n>>s;
    s+='H';
    for(int i=1;i<=n;i++)
    	cin>>a[i];
    for(int i=1;i<=n;i++)
    {
        lianbiao[i].before=i-1;
        lianbiao[i].next=i+1;
    }
    for(int i=1;i<n;i++)
        if(s[i-1]!=s[i])
            qpush(i,i+1,abs(a[i]-a[i+1]));
    while(!q.empty())
    {
        node now=q.top();
        q.pop();
        if(vis[now.qian]==false&&vis[now.hou]==false)
        {
            lianbiao[lianbiao[now.qian].before].next=lianbiao[now.hou].next;
            lianbiao[lianbiao[now.hou].next].before=lianbiao[now.qian].before;
            sum++;
            ans1[sum]=now.qian;
            ans2[sum]=now.hou;
            vis[now.qian]=true;
            vis[now.hou]=true;
            if(now.qian!=1&&now.hou!=n&&vis[lianbiao[now.qian].before]==false&&vis[lianbiao[now.hou].next]==false&&s[lianbiao[now.qian].before-1]!=s[lianbiao[now.hou].next-1])
                qpush(lianbiao[now.qian].before,lianbiao[now.hou].next,abs(a[lianbiao[now.qian].before]-a[lianbiao[now.hou].next]));
        }
    }
    cout<<sum<<endl;
    for(int i=1;i<=sum;i++)
        cout<<ans1[i]<<" "<<ans2[i]<<endl;
    return 0;
}