ZOJ Supermarket

http://acm.zju.edu.cn/onlinejudge/showProblem.do?problemId=524

LCS   细节

#include <iostream>
#include <cstdio>
#include <vector>
#include <cmath>
#include <set>
#include <map>
#include <queue>
#include <string>
#include <cstring>
#include <algorithm>

//int f_min(int x,int y) {if(x<y)return x; else return y;}
//int f_max(int x,int y) {if(x<y)return y; else return x;}
//int f_abs(int x) {return (x)>(0)?(x):(-x);}
int lowbit(int x) {return (x)&(-x);}
double f_min(double x,double y) {if(x<y)return x; else return y;}
double f_max(double x,double y) {if(x<y)return y; else return x;}
using namespace std;

const int MM = 511111;
const double Pi = acos(-1.0);
const double lep = 1e-6;
const double inf = 1000000000.00;
#define debug puts("wrong")
#define maxint 0x3f3f3f3f
#define lson rt<<1
#define rson rt<<1|1
//typedef __int64 int64;
//typedef long long int64;
//const __int64 maxint = 1000000000000000;

int N,M;
int num[MM], Q;
int list[MM];
struct Info {
    int id;
    double val;
}p[MM];
struct Union_set {
    int fa[MM];
    int rank[MM];
    void reset(int n) {
        for(int i=0;i<=n;i++) {
            fa[i]=i;
            rank[i]=0;
        }
    }
    int getfa(int x) {return fa[x]==x?x:fa[x]=getfa(fa[x]);}
    void join(int x,int y) {
        int xx=getfa(x), yy=getfa(y);
        if(xx==yy) return;
        else {
            if(rank[xx]>rank[yy]) fa[yy]=xx;
            else {
                if(rank[xx]<rank[yy]) fa[xx]=yy;
                else { fa[xx]=yy; rank[yy]++; }
            }
        }
    }
}Unset;

double dp[2][MM];
void get_data() {
    int i,j,k;
    for(i=1;i<=N;i++) scanf("%d",&list[i]);
    for(i=1;i<=M;i++) scanf("%d%lf",&p[i].id,&p[i].val);
}
void solve() {
    int i,j,k;
    int now=0, pre=1;
    for(i=0;i<=M;i++) dp[now][i]=inf;
    for(i=1;i<=M;i++) {
        if(p[i].id==list[1]) dp[now][i]=f_min(dp[now][i-1],p[i].val);
        else dp[now][i]=dp[now][i-1];
    }
//    for(i=1;i<=M;i++) printf("%.2lf ",dp[now][i]); printf("\n");
    for(i=2;i<=N;i++) {
        for(j=0;j<=M;j++) dp[pre][j]=inf;
        for(j=1;j<=M;j++) {
            if(p[j].id==list[i]) dp[pre][j]=f_min(dp[pre][j-1],dp[now][j-1]+p[j].val);
            else dp[pre][j]=dp[pre][j-1];
        }
        now=pre, pre^=1;
    }
    double ans=inf;
    for(i=0;i<=M;i++) {
        if(ans>dp[now][i]) ans=dp[now][i];
    }
    if(ans<inf) printf("%.2lf\n",ans);
    else puts("Impossible");
}
int main() {
    while(scanf("%d%d",&N,&M),N+M) get_data(),solve();
    return 0;
}