[CodeForces] [思维] NEKO's Maze Game

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Thinking questions, would like to see is extremely simple.

First, consider the circumstances under which the road will be sealed:

There are three cases.

So obviously we do not need each time from 1 to n there is no way to find it again, each change of status on a plaid check the status of another column three grid can be. And then stored in a variable ans enough about the total number of blocked road grid. ans is zero YES, otherwise NO.

Code

 1 #include<bits/stdc++.h>
 2 using namespace std;
 3 const int maxn=100000+5;
 4 bool a[maxn],b[maxn];
 5 int n,q;
 6 int main(){
 7     ios::sync_with_stdio(false);
 8     cin>>n>>q;
 9     int ans=0;
10     for(int i=1;i<=q;i++){
11         int x,y;
12         cin>>x>>y;
13         if(x==1){
14             if(a[y]){
15                 a[y]=0;
16                 if(b[y]) ans--;
17                 if(b[y+1]) ans--;
18                 if(b[y-1]) ans--;
19             }
20             else{
21                 a[y]=1;
22                 if(b[y]) ans++;
23                 if(b[y+1]) ans++;
24                 if(b[y-1]) ans++;
25             }
26         }
27         else{
28             if(b[y]){
29                 b[y]=0;
30                 if(a[y]) ans--;
31                 if(a[y+1]) ans--;
32                 if(a[y-1]) ans--;
33             }
34             else{
35                 b[y]=1;
36                 if(a[y]) ans++;
37                 if(a[y+1]) ans++;
38                 if(a[y-1]) ans++;
39             }
40         }
41         if(ans) cout<<"No"<<endl;
42         else cout<<"Yes"<<endl;
43     }
44     return 0;
45 }

View Code

(I was back playing table when the entry-feeling)

 

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