学步园

先把已知路段的距离设为0，然后prim

code

/*
ID: yueqiq
PROG: numtri
LANG: C++
*/
#include <set>
#include <map>
#include <ctime>
#include <queue>
#include <cmath>
#include <stack>
#include <limits>
#include <vector>
#include <bitset>
#include <string>
#include <cstdio>
#include <cstring>
#include <fstream>
#include <string.h>
#include <iostream>
#include <algorithm>
#define Si set<int>
#define LL long long
#define pb push_back
#define PS printf(" ")
#define Vi vector<int>
#define LN printf("\n")
#define lson l,m,rt << 1
#define rson m+1,r,rt<<1|1
#define SD(a) scanf("%d",&a)
#define PD(a) printf("%d",a)
#define SET(a,b) memset(a,b,sizeof(a))
#define FF(i,a) for(int i(0);i<(a);i++)
#define FD(i,a) for(int i(a);i>=(1);i--)
#define FOR(i,a,b) for(int i(a);i<=(b);i++)
#define FOD(i,a,b) for(int i(a);i>=(b);i--)
#define readf freopen("input.txt","r",stdin)
#define writef freopen("output.txt","w",stdout)
const int maxn = 101;
const int INF = 1111;
const int dx[]={0,1,0,-1};
const int dy[]={1,0,-1,0};
const double pi = acos(-1.0);
const double eps= 1e-7;
using namespace std;
int N,M;
int edge[maxn][maxn];
int dis[maxn];
bool vis[maxn];
int prim(){
    SET(vis,false);
    int s=1;
    FOR(i,1,N) dis[i]=edge[1][i];
    vis[s]=true;
    int minn;
    int ans=0;
    FOR(i,1,N-1){
        minn=INF;
        FOR(j,1,N){
            if(!vis[j] && dis[j]<minn){
                minn=dis[j];
                s=j;
            }
        }
        vis[s]=true;
        ans+=minn;
        FOR(j,1,N){
            if(!vis[j] && dis[j]>edge[s][j])
                dis[j]=edge[s][j];
        }
    }
    return ans;
}
int main()
{
    while(~scanf("%d",&N)){
        FOR(i,1,N) FOR(j,1,N) edge[i][j]=INF;
        FOR(i,1,N) FOR(j,1,N){
            SD(edge[i][j]);
        }
        SD(M);
        int a,b;
        FOR(i,1,M){
            SD(a);SD(b);
            edge[a][b]=edge[b][a]=0;
        }
        PD(prim());LN;
    }
    return 0;
}