位运算的题……基本都是按位来做的？。。。
从高位到低位，贪心来搞就可以了……
这都算不上是数位DP吧= =
1 /************************************************************** 2 Problem: 3668 3 User: Tunix 4 Language: C++ 5 Result: Accepted 6 Time:340 ms 7 Memory:2052 kb 8 ****************************************************************/ 9 10 //BZOJ 3668 11 #include<vector> 12 #include<cstdio> 13 #include<cstring> 14 #include<cstdlib> 15 #include<iostream> 16 #include<algorithm> 17 #define rep(i,n) for(int i=0;i<n;++i) 18 #define F(i,j,n) for(int i=j;i<=n;++i) 19 #define D(i,j,n) for(int i=j;i>=n;--i) 20 using namespace std; 21 typedef long long LL; 22 inline int getint(){ 23 int r=1,v=0; char ch=getchar(); 24 for(;!isdigit(ch);ch=getchar()) if (ch=='-') r=-1; 25 for(; isdigit(ch);ch=getchar()) v=v*10-'0'+ch; 26 return r*v; 27 } 28 const int N=1e5+10; 29 /*******************template********************/ 30 31 int n,m,a[N],lim[40],op[N]; 32 33 int opt(int a,int b,int k){ 34 if (k==0) return a&b; 35 if (k==1) return a|b; 36 return a^b; 37 } 38 int main(){ 39 #ifndef ONLINE_JUDGE 40 freopen("3668.in","r",stdin); 41 freopen("3668.out","w",stdout); 42 #endif 43 n=getint(); m=getint(); 44 F(i,0,30) lim[i]=m>>i&1; 45 char s[5]; 46 F(i,1,n){ 47 scanf("%s",s); a[i]=getint(); 48 if (s[0]=='A') op[i]=0; 49 if (s[0]=='O') op[i]=1; 50 if (s[0]=='X') op[i]=2; 51 } 52 bool sign=1; 53 int ans=0; 54 D(i,30,0){ 55 int now=1,tmp0=0,tmp1=1; 56 F(j,1,n) 57 tmp0=opt(tmp0,a[j]>>i&1,op[j]), 58 tmp1=opt(tmp1,a[j]>>i&1,op[j]); 59 if ((tmp0>=tmp1) || (sign && lim[i]==0)){ 60 if (lim[i]==1) sign=0; 61 ans|=tmp0<<i; 62 }else ans|=tmp1<<i; 63 } 64 printf("%d\n",ans); 65 return 0; 66 }