貪心

我們的目標一定是讓最終答案的二進位制位的高位儘量為1
發現位運算只會影響一位
於是搞貪心

#include<cstdio>
#define N 100005
using namespace std;
struct door
{
    int op, t;
    int make(int x)
    {
        if(op==1)return x|t;
        if(op==2)return x&t;
        return x^t;
    } 
}d[N];
char s[5]; 
int n, m, now, ans;
int go(int
 
 x)
{
    for(int i = 1; i <= n; i++)
        x=d[i].make(x);
    return x;
}
int main()
{
    scanf("%d%d",&n,&m);
    for(int i = 1; i <= n; i++)
    {
        scanf("%s%d",s,&d[i].t);
        if(s[0]=='A')d[i].op=2;
        else if(s[0]=='O')d[i].op=1;
        else d[i].op=0;
    }
    for
 
(now=1;now<=m;now<<=1);
    for(now>>=1;now;now>>=1)
    {
        if(go(0)&now)
            continue;
        if(ans+now<=m&&(go(now)&now))
            ans+=now;
    }
    printf("%d\n",go(ans));
}