系统告诉我 reference to 'plus' is ambigous

啥意思？

说明了啥？

#include<bits/stdc++.h>
#define printlf(x) print(x),putchar('\n')
#define printsp(x) print(x),putchar(' ')
using namespace std;
inline int read(){
    int x=0;
    bool w=0;
    char c=getchar();
    while(!isdigit(c))  w|=c=='-',c=getchar();
    while(isdigit(c))   x=(x<<1)+(x<<3)+(c^48),c=getchar();
    return w?-x:x;
}
inline void print(int x){
    if(x<0) x=-x,putchar('-');
    if(x>9) print(x/10);
    putchar('0'+x%10);
}
struct node{
	int x,y;
	bool operator <(const node &p) const{
		return p.x<x;
	}
};
int n,m;
const int N=105;
int a[N][N],vis[N][N];
vector<node> plus;
const int dx[4]={1,-1,0,0};
const int dy[4]={0,0,1,-1};
inline int flood_fill(node in){
	plus.clear();
	queue<node> q;
	q.push(in);
	int res=0,cnt=0;
	while(!q.empty()){
		node tmp=q.front();q.pop();
		int x=tmp.x,y=tmp.y;
		for(register int i=0;i<4;++i){
			int xx=x+dx[i],yy=y+dy[i];
			if(a[xx][yy]>a[in.x][in.y])	{
				if(vis[xx][yy])	vis[xx][yy]=0;
				else	plus.push_back=(node){xx,yy};
			}
			if(a[xx][yy]<a[in.x][in.y] && xx>0 && yy>0 && xx<=n && yy<=m)	
				q.push((node){xx,yy}),res+=a[xx][yy];
		}
	}
	return res;
}
inline void Solve(){
	int ans=0;
	priority_queue<node> Q;
	for(register int i=2;i<n;++i)	Q.push((node){i,1}),Q.push((node){i,n}),vis[i][1]=vis[i][n]=1;
	for(register int i=2;i<m;++i)	Q.push((node){1,i}),Q.push((node){n,i}),vis[1][i]=vis[n][i]=1;
	Q.push((node){1,1}),Q.push((node){1,n}),Q.push((node){n,1}),Q.push((node){n,n});
	vis[1][1]=vis[1][n]=vis[n][n]=vis[n][1]=1;
	while(!Q.empty()){
		node tmp=Q.top();Q.pop();
		if(!vis[tmp.x][tmp.y])	continue;
		ans+=flood_fill(tmp);
		for(register int i=0;i<plus.size();++i)
			Q.push(plus[i]);
	}
	printlf(ans);
}
signed main(){
	int T=read();
	while(T--){
		n=read(),m=read();
		for(register int i=1;i<=n;++i)
			for(register int j=1;j<=m;++j)	
				a[i][j]=read();
		Solve();
	}
    return 0;
}