hdu1158Employment Planning

我有两个想法，其中一个超时，另外一个不知道怎么表达，结果悲剧地看了答案，可惜正确的答案跟我的想法一样

ACCEPT

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

using namespace std;

const int N = 10000;
const int inf = 0xfffffff;

int mon[13];
int dp[13][N];

int main()
{
    //freopen("data.in", "r", stdin);

    int m, i, j, k;
    while(scanf("%d", &m), m)
    {
        int hire, fire, salary, max, min, cost;

        memset(dp, 0, sizeof(dp));
        memset(mon, 0, sizeof(mon));

        scanf("%d%d%d", &hire, &salary, &fire);
        max = -inf;

        for(i = 1; i <= m; i++)
        {
            scanf("%d", mon + i);
            max = max > mon[i] ? max : mon[i];
        }

        for(i = mon[1]; i <= max; i++)
            dp[1][i] = (hire+salary) * i;

        for(i = 2; i <= m; i++)
        {
            for(j = mon[i]; j <= max; j++)
            {
                min = inf;
                for(k = mon[i-1]; k <= max; k++)
                {
                    if(k <= j)
                        cost = (j-k)*hire + j*salary + dp[i-1][k];
                    else
                        cost = (k-j)*fire + j*salary + dp[i-1][k];
                    if(min > cost)
                        min = cost;
                }
                //printf("%d
", min);
                dp[i][j] = min;
            }
        }

        min = inf;
        for(i = mon[m]; i <= max; i++)
            if(min > dp[m][i])
                min = dp[m][i];
        printf("%d
", min);
    }
    return 0;
}

我的代码，搜索，超时了

#include "iostream"
#define INF 1000000000
using namespace std;
int best=INF,n,hire,salay,fire,i,num[1100];
void dfs(int month,int cost,int much){
  cost+=much*salay;
  if(month==n){
    //cout<<"cost "<<cost<<endl;
    if(best>cost){best=cost;return;}
    else return;
  }
  //cout<<"month "<<month<<" cost "<<cost<<endl;
  if(much==num[month+1])dfs(month+1,cost,much);
  else if(much<num[month+1]){cost+=(num[month+1]-much)*hire;much=num[month+1];dfs(month+1,cost,much);}
  else {
    int ans=much-num[month+1];
    for(int i=0;i<=ans;i++){
      dfs(month+1,cost+i*fire,much-i);
    }
  }
}
int main(){
  int cost;
  while(1){
    cin>>n;
    if(!n)break;
    cin>>hire>>salay>>fire;
    for(i=1;i<=n;i++)cin>>num[i];
    best=INF;
    cost=num[1]*hire;
    dfs(1,cost,num[1]);
    cout<<best<<endl;
  }
}