[数位DP] BZOJ1190. [HNOI2007]梦幻岛宝珠

#include <cstdio>
#include <iostream>
#include <algorithm>
#include <cstring>

using namespace std;

const int N=110;

typedef long long ll;

int n,w;
struct A{
int x,y,k;
friend bool operator <(const A &a,const A &b){
return a.k<b.k;
}
}a
;
ll f[40][1010][2];

inline void fix(ll &x,ll y){
if(x<y) x=y;
}

int main(){
while(~scanf("%d%d",&n,&w)){
if(n==-1 && w==-1) break;
for(int i=1;i<=n;i++){
scanf("%d%d",&a[i].x,&a[i].y); a[i].k=0;
while(a[i].x%2==0) a[i].x/=2,a[i].k++;
}
sort(a+1,a+1+n);
memset(f,0,sizeof(f));
for(int i=1;i<=n && a[i].k==0;i++)
for(int j=1000;j>=a[i].x;j--)
fix(f[0][j][0],f[0][j-a[i].x][0]+a[i].y);
int i,l,r;
for(i=0,l=1,r=0;(1<<i+1)<=w;i++){
while(a[l].k<=i && l<=n) l++;
while(a[r+1].k<=i+1 && r<n) r++;
for(int j=0;j<=1000;j++){
if(j&1){
if(w>>i&1) fix(f[i+1][j>>1][0],f[i][j][0]),fix(f[i+1][j>>1][1],f[i][j][1]);
else fix(f[i+1][j>>1][1],f[i][j][0]),fix(f[i+1][j>>1][1],f[i][j][1]);
}
else{
if(w>>i&1) fix(f[i+1][j>>1][0],f[i][j][0]),fix(f[i+1][j>>1][0],f[i][j][1]);
else fix(f[i+1][j>>1][0],f[i][j][0]),fix(f[i+1][j>>1][1],f[i][j][1]);
}
}
for(int j=l;j<=r;j++)
for(int k=1000;k>=a[j].x;k--)
fix(f[i+1][k][0],f[i+1][k-a[j].x][0]+a[j].y),fix(f[i+1][k][1],f[i+1][k-a[j].x][1]+a[j].y);
for(int j=1;j<=1000;j++)
fix(f[i+1][j][0],f[i+1][j-1][0]),fix(f[i+1][j][1],f[i+1][j-1][1]);
}
printf("%lld\n",f[i][1][0]);
}
return 0;
}