[题解]SP703 SERVICE

设计状态F[i][j][k]代表完成任务i后,有一个员工在地点P[i],其他两人分别在j和k两地。所需要的最小代价。

转移的方式:

分别考虑派遣i,j,k三人前往下一个需求地点,并更新状态。

#include <iostream>
#include <stdio.h>
#include <string.h>
#define re register
#define GC getchar()
#define Clean(X,K) memset(X,K,sizeof(X))
#include <iostream>
#define Max(A,B) ((A)>(B)?(A):(B))
#define Min(A,B) ((A)<(B)?(A):(B))
using namespace std ;
int Qread () {
    int X = 0 ;
    char C = GC ;
    while (C > '9' || C < '0') C = GC ;
    while (C >='0' && C <='9') {
        X = X * 10 + C - '0' ;
        C = GC ;
    }
    return X ;
}
const int Maxl = 205 , Maxn = 1005 ,INF = 20021020 << 2;
int C[Maxl][Maxn] , N , L , Times , Q[Maxn] = {1}, F[Maxn][Maxl][Maxl];
int main () {
//    freopen ("SP703.in" , "r" , stdin) ;
    Times = Qread () ;
    while (Times -- ) {
        Clean (F , 0) ;
        L = Qread () , N = Qread () ;
        for (re int i = 1 ; i <= L; ++ i) for (re int j = 1 ; j <= L; ++ j) C[i][j] = Qread () ;
        for (re int i = 1 ; i <= N; ++ i) Q[i] = Qread () ;
        Clean (F , 0x3f) ;
        F[0][2][3] = 0 ;
        for (re int i = 0 ; i < N; ++ i) {
            for (re int j = 1 ; j <= L ; ++ j) {
                for (re int k = 1 ; k <= L; ++ k) {
                    if (Q[i] == j || Q[i] == k || j == k) continue ;
                    F[i + 1][j][k] = Min (F[i + 1][j][k] ,F[i][j][k] +  C[Q[i]][Q[i + 1]]) ;
                    F[i + 1][Q[i]][k] = Min (F[i + 1][Q[i]][k] , F[i][j][k] + C[j][Q[i + 1]]) ;
                    F[i + 1][j][Q[i]] = Min (F[i + 1][j][Q[i]] , F[i][j][k] + C[k][Q[i + 1]]) ;
                }
            }
        }
        int Ans = INF ;
        for (re int i = 1 ; i <= L ; ++ i) {
            for (re int j = 1 ; j <= L; ++ j) {
                Ans = Min (Ans , F[N][i][j]) ;
            }
        }
        printf ("%d
" , Ans) ;
    }
    fclose (stdin) , fclose (stdout) ;
    return 0 ;
}
原文地址:https://www.cnblogs.com/bj2002/p/10683010.html