思维——cf1238C

#include<bits/stdc++.h>
using namespace std;
#define N 200005
int n,p[N],h;
vector<int>v;

int main(){
    int q;cin>>q;
    while(q--){
        v.clear();
        cin>>h>>n;
        int len=0;
        for(int i=1;i<=n;i++){
            cin>>p[i];
            if(i==1 || p[i]+1==p[i-1])
                len++;
            else {
                if(v.size()!=0)len++;
                v.push_back(len);
                len=1;
            }
        }
        
        int ans=0;
        if(p[n]>=2){
            if(v.size())len++;
            if(len%2==0)ans++;
        } 
        
        
        for(auto len:v){
            if(len%2==0)ans++;
        }
        
        cout<<ans<<‘\n‘;
    }
}