Luogu2114 [NOI2014]起床困难综合症 【位运算】

题目分析：

按位处理即可

代码：

 #include<bits/stdc++.h>
 using namespace std;

 const int maxn = ;

 int n,m;
 int a[maxn],b[maxn];

 void work(){
     int z = ;
     for(int i=;i>=;i--){
     if((<<i)+z > m)continue;
     int l = (<<i),r=;
     for(int i=;i<=n;i++){
         if(a[i] == ) l = (l&b[i]),r = (r&b[i]);
         else if(a[i] == ) l = (l|b[i]),r = (r|b[i]);
         else l = (l^b[i]),r = (r^b[i]);
     }
     if((r&(<<i)) != ) continue;
     if((l&(<<i)) == ) continue;
     z += (<<i);
     }
     for(int i=;i<=n;i++){
     if(a[i] == ) z = (z&b[i]);
     else if(a[i] == ) z=  (z|b[i]);
     else z = (z^b[i]);
     }
     printf("%d\n",z);
 }

 int main(){
     scanf("%d%d",&n,&m);
     for(int i=;i<=n;i++){
     char ch = getchar();
     while(ch > 'Z' || ch < 'A') ch = getchar();
     if(ch == 'A'){a[i] = ;}
     else if(ch == 'O'){a[i] = ;}
     else a[i] = ;
     while(ch  != ' ') ch = getchar();
     scanf("%d",&b[i]);
     }
     work();
     return ;
 }