学步园

比赛的时候写脑残了，其实挺简单的一题。变量有三个，时间，生命值和攻击力，时间是肯定要存的然后比较之后觉得存攻击力的话专一起来方便一些。然后就木有然后了，状态设计为dp[i][j]表示当前时间为i攻击力为j所剩余的最小生命值，当然小于等于0的时候就表示已经挂了。输出答案自己很好找。另外，转移来自两个方面，以方便是从当前时间直接转到+1时间，这个不造新的舰船，还有就是制造了新的舰船的情况，直接在制造时间上转移。

/*
 Author : Speedcell
 Update : 2013-03-23
Version : soppYcell 2.1
*/

#include <algorithm>
#include <iostream>
#include <fstream>
#include <sstream>
#include <iomanip>

#include <map>
#include <set>
#include <list>
#include <stack>
#include <queue>
#include <deque>
#include <vector>
#include <string>
#include <bitset>
#include <memory>
#include <complex>
#include <numeric>

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <time.h>
#include <ctype.h>
#include <locale.h>

using namespace std;

#pragma pack(4)

#ifndef __CONSTANT__
#define __CONSTANT__

typedef long long LONG;

const double pi = acos(-1.0);
const int   inf = 0x7f7f7f7f;
const LONG  INF = 0x7f7f7f7f7f7f7f7fll;

const int go[8][2] = {{0,1},{0,-1},{1,0},{-1,0},{1,1},{1,-1},{-1,1},{-1,-1}};

#endif // __CONSTANT__

#ifndef __IO__
#define __IO__

inline bool RD(int    & a) {return scanf("%d",&a)!=EOF;}
inline bool RD(char   & a) {return scanf("%c",&a)!=EOF;}
inline bool RD(char   * a) {return scanf("%s", a)!=EOF;}
inline bool RD(double & a) {return scanf("%lf",&a)!=EOF;}
inline bool RD(LONG   & a) {return scanf("%I64d",&a)!=EOF;}

template<class T1> inline bool
    IN(T1 & a) {return RD(a);}
template<class T1,class T2> inline bool
    IN(T1 & a,T2 & b) {return RD(a)&&RD(b);}
template<class T1,class T2,class T3> inline bool
    IN(T1 & a,T2 & b,T3 & c) {return RD(a)&&RD(b)&&RD(c);}
template<class T1,class T2,class T3,class T4> inline bool
    IN(T1 & a,T2 & b,T3 & c,T4 & d) {return RD(a)&&RD(b)&&RD(c)&&RD(d);}
template<class T1,class T2,class T3,class T4,class T5> inline bool
    IN(T1 & a,T2 & b,T3 & c,T4 & d,T5 & e) {return RD(a)&&RD(b)&&RD(c)&&RD(d)&&RD(e);}
template<class T1,class T2,class T3,class T4,class T5,class T6> inline bool
    IN(T1 & a,T2 & b,T3 & c,T4 & d,T5 & e,T6 & f) {return RD(a)&&RD(b)&&RD(c)&&RD(d)&&RD(e)&&RD(f);}
template<class T1,class T2,class T3,class T4,class T5,class T6,class T7> inline bool
    IN(T1 & a,T2 & b,T3 & c,T4 & d,T5 & e,T6 & f,T7 & g) {return RD(a)&&RD(b)&&RD(c)&&RD(d)&&RD(e)&&RD(f)&&RD(g);}

inline void PT(int    a) {printf("%d",a);}
inline void PT(char   a) {printf("%c",a);}
inline void PT(double a) {printf("%f",a);}
inline void PT(LONG   a) {printf("%I64d",a);}
inline void PT(string a) {printf("%s",a.begin());}

template<class T1> inline void
    OT(T1 a) {PT(a);}
template<class T1,class T2> inline void
    OT(T1 a,T2 b) {PT(a),PT(' '),PT(b);}
template<class T1,class T2,class T3> inline void
    OT(T1 a,T2 b,T3 c) {PT(a),PT(' '),PT(b),PT(' '),PT(c);}
template<class T1,class T2,class T3,class T4> inline void
    OT(T1 a,T2 b,T3 c,T4 d) {PT(a),PT(' '),PT(b),PT(' '),PT(c),PT(' '),PT(d);}
template<class T1,class T2,class T3,class T4,class T5> inline void
    OT(T1 a,T2 b,T3 c,T4 d,T5 e) {PT(a),PT(' '),PT(b),PT(' '),PT(c),PT(' '),PT(d),PT(' '),PT(e);}
template<class T1,class T2,class T3,class T4,class T5,class T6> inline void
    OT(T1 a,T2 b,T3 c,T4 d,T5 e,T6 f) {PT(a),PT(' '),PT(b),PT(' '),PT(c),PT(' '),PT(d),PT(' '),PT(e),PT(' '),PT(f);}
template<class T1,class T2,class T3,class T4,class T5,class T6,class T7> inline void
    OT(T1 a,T2 b,T3 c,T4 d,T5 e,T6 f,T7 g) {PT(a),PT(' '),PT(b),PT(' '),PT(c),PT(' '),PT(d),PT(' '),PT(e),PT(' '),PT(f),PT(' '),PT(g);}

inline void PL(int    a) {printf("%d\n",a);}
inline void PL(char   a) {printf("%c\n",a);}
inline void PL(double a) {printf("%f\n",a);}
inline void PL(LONG   a) {printf("%I64d\n",a);}
inline void PL(string a) {printf("%s\n",a.begin());}

template<class T1> inline void
    OL(T1 a) {PL(a);}
template<class T1,class T2> inline void
    OL(T1 a,T2 b) {PT(a),PT(' '),PL(b);}
template<class T1,class T2,class T3> inline void
    OL(T1 a,T2 b,T3 c) {PT(a),PT(' '),PT(b),PT(' '),PL(c);}
template<class T1,class T2,class T3,class T4> inline void
    OL(T1 a,T2 b,T3 c,T4 d) {PT(a),PT(' '),PT(b),PT(' '),PT(c),PT(' '),PL(d);}
template<class T1,class T2,class T3,class T4,class T5> inline void
    OL(T1 a,T2 b,T3 c,T4 d,T5 e) {PT(a),PT(' '),PT(b),PT(' '),PT(c),PT(' '),PT(d),PT(' '),PL(e);}
template<class T1,class T2,class T3,class T4,class T5,class T6> inline void
    OL(T1 a,T2 b,T3 c,T4 d,T5 e,T6 f) {PT(a),PT(' '),PT(b),PT(' '),PT(c),PT(' '),PT(d),PT(' '),PT(e),PT(' '),PL(f);}
template<class T1,class T2,class T3,class T4,class T5,class T6,class T7> inline void
    OL(T1 a,T2 b,T3 c,T4 d,T5 e,T6 f,T7 g) {PT(a),PT(' '),PT(b),PT(' '),PT(c),PT(' '),PT(d),PT(' '),PT(e),PT(' '),PT(f),PT(' '),PL(g);}

#endif // __IO__

#ifndef __MACRO__
#define __MACRO__

#define ML(times) int tcase; IN(tcase); FOR(times,1,tcase)

#define FOR(i,a,b) for(int i=int(a),_##i=int(b);i<=_##i;i++)
#define DWN(i,b,a) for(int i=int(b),_##i=int(a);_##i<=i;i--)
#define ECH(i,u,pre,next) for(int i=int(pre[u]);i!=-1;i=int(next[i]))

#define MEM(a,v) memset(a,v,sizeof(a))
#define CLR(a,v) FOR(_i##a,0,sizeof(a)/sizeof(a[0])-1) a[_i##a]=v

#define LOOP(a,n)                                               \
    FOR(_i##a,0,n-1)                                            \
        cout<<a[_i##a]<<(_i##a!=n-1?' ':'\n')
#define LOOP2(a,n,m)                                            \
    FOR(_i##a,0,n-1) FOR(_j##a,0,m-1)                           \
        cout<<a[_i##a][_j##a]<<(_j##a!=m-1?' ':'\n')
#define LOOPG(G,n,pre,next)                                     \
    FOR(_i##a,0,n-1) ECH(_j##a,_i##a,pre,next)                  \
        cout<<_i##a<<" "<<G[_j##a].v<<" "<<G[_j##a].w<<endl

#endif // __MACRO__

#ifndef __BIT__
#define __BIT__

template<class T> inline T lb(T i) {return i&-i;}
template<class T> inline T lc(T i) {return i<<T(1);}
template<class T> inline T rc(T i) {return i<<T(1)|T(1);}
template<class T> inline T at(T a,int i) {return a& (T(1)<<i);}
template<class T> inline T nt(T a,int i) {return a^ (T(1)<<i);}
template<class T> inline T s1(T a,int i) {return a| (T(1)<<i);}
template<class T> inline T s0(T a,int i) {return a&~(T(1)<<i);}

#endif // __BIT__

#ifndef __DOUBLE__
#define __DOUBLE__

const double eps = 1e-8;

inline int cmp(double a) {return fabs(a-0)<eps?0:((a-0)>eps?+1:-1);}
inline int cmp(double a,double b) {return fabs(a-b)<eps?0:((a-b)>eps?+1:-1);}

inline double fmax(double a,double b) {return cmp(a,b)>0?a:b;}
inline double fmin(double a,double b) {return cmp(a,b)<0?a:b;}

#endif // __DOUBLE__

const int MAXV = 400;

int n,m,t[MAXV],l[MAXV],dp[MAXV][MAXV];

int check(int n,int m)
{
    FOR(i,0,MAXV-1)
    {
        FOR(j,0,MAXV-1) if(dp[i][j]<=0) return i;
    }
}

int main()
{
    #ifndef ONLINE_JUDGE
    freopen("Battle Ships.txt","r",stdin);
    #else
    #endif

    while(IN(n,m))
    {
        FOR(i,0,n-1) IN(t[i],l[i]);
        MEM(dp,inf); dp[0][0]=m;
        FOR(i,0,MAXV-1)
        {
            FOR(j,0,MAXV-1)
            {
                if(MAXV>i+1)
                    dp[i+1][j]=min(dp[i+1][j],dp[i][j]-j);
                FOR(k,0,n-1)
                {
                    if(MAXV>i+t[k]&&MAXV>j+l[k])
                        dp[i+t[k]][j+l[k]]=min(dp[i+t[k]][j+l[k]],dp[i][j]-j*t[k]);
                }
            }
        }
        OL(check(n,m));
    }

    return 0;
}