洛谷P1194 买礼物

 1 #include <bits/stdc++.h> 
 2 #define LL long long 
 3 #define For(i,j,k) for(int i=j;i<=k;i++)  
 4 using namespace std ; 
 5 
 6 const int N = 511,inf = 1e9 ; 
 7 int A,n,sum ; 
 8 int dist[N],a[N][N] ; 
 9 bool visit[N] ; 
10 
11 inline LL read() 
12 {
13     LL x = 0 , f = 1 ; 
14     char ch = getchar() ; 
15     while(ch<‘0‘||ch>‘9‘) { if(ch==‘-‘) f = -1 ; ch = getchar() ; } 
16     while(ch>=‘0‘&&ch<=‘9‘) { x = x * 10+ch-48 ; ch = getchar() ; } 
17     return x * f ;  
18 }
19 
20 inline void prim() 
21 {
22     For(i,1,n) visit[ i ] = 0 , dist[ i ] = inf ; 
23     dist[ 1 ] = 0 ;  dist[ 0 ] = inf ; 
24     int k ; 
25     For(i,1,n) {
26         k = 0 ; 
27         For(j,1,n) 
28             if(!visit[j]&&dist[j] < dist[ k ] ) k = j ; 
29         visit[ k ] = 1 ; 
30         For(j,1,n) 
31             if(!visit[j]&&a[k][j] < dist[ j ]) dist[ j ] = a[ k ][ j ] ; 
32     }
33     For(i,1,n) sum+=dist[ i ] ; 
34     sum+=A ; 
35     printf("%d\n",sum) ; 
36 }
37 
38 int main() 
39 {
40     A = read() ; n = read() ; 
41     For(i,1,n) 
42         For(j,1,n) {
43             a[ i ][ j ] = read() ; 
44             if(a[ i ][ j ] == 0) a[ i ][ j ] = inf ; 
45         }
46     prim() ; 
47     return 0 ; 
48 }