http://www.lydsy.com/JudgeOnline/problem.php?id=1624
一开始我打算一个个最短路。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。
然后没想到。。。。。floyd。。。
吐血。。
很简单,裸floyd即可。
#include <cstdio> #include <cstring> #include <cmath> #include <string> #include <iostream> #include <algorithm> #include <queue> using namespace std; #define rep(i, n) for(int i=0; i<(n); ++i) #define for1(i,a,n) for(int i=(a);i<=(n);++i) #define for2(i,a,n) for(int i=(a);i<(n);++i) #define for3(i,a,n) for(int i=(a);i>=(n);--i) #define for4(i,a,n) for(int i=(a);i>(n);--i) #define CC(i,a) memset(i,a,sizeof(i)) #define read(a) a=getint() #define print(a) printf("%d", a) #define dbg(x) cout << #x << " = " << x << endl #define printarr(a, n, m) rep(aaa, n) { rep(bbb, m) cout << a[aaa][bbb]; cout << endl; } inline const int getint() { int r=0, k=1; char c=getchar(); for(; c<'0'||c>'9'; c=getchar()) if(c=='-') k=-1; for(; c>='0'&&c<='9'; c=getchar()) r=r*10+c-'0'; return k*r; } inline const int max(const int &a, const int &b) { return a>b?a:b; } inline const int min(const int &a, const int &b) { return a<b?a:b; } const int N=105; int f[N][N], n, m, a[10005]; long long ans; int main() { read(n); read(m); for1(i, 1, m) read(a[i]); for1(i, 1, n) for1(j, 1, n) read(f[i][j]); for1(k, 1, n) for1(i, 1, n) for1(j, 1, n) f[i][j]=min(f[i][j], f[i][k]+f[k][j]); for1(i, 2, m) ans+=f[a[i-1]][a[i]]; ans+=f[1][a[1]]; ans+=f[a[m]][n]; printf("%lld", ans); return 0; }
Description
Input
Output
Sample Input
1
2
1
3
0 5 1
5 0 2
1 2 0
INPUT DETAILS:
There are 3 islands and the treasure map requires Farmer John to
visit a sequence of 4 islands in order: island 1, island 2, island
1 again, and finally island 3. The danger ratings of the paths are
given: the paths (1, 2); (2, 3); (3, 1) and the reverse paths have
danger ratings of 5, 2, and 1, respectively.
Sample Output
OUTPUT DETAILS:
He can get the treasure with a total danger of 7 by traveling in
the sequence of islands 1, 3, 2, 3, 1, and 3. The cow map's requirement
(1, 2, 1, and 3) is satisfied by this route. We avoid the path
between islands 1 and 2 because it has a large danger rating.
HINT
Source
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