洛谷 P2243 电路维修

#include<queue>
#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
#define MAXN 350010
using namespace std;
char s[1010];
int t,r,c,tot;
int vis[MAXN],dis[MAXN];
int to[MAXN*2],net[MAXN*2],cap[MAXN*2],head[MAXN*2];
void add(int u,int v,int w){
    to[++tot]=v;net[tot]=head[u];cap[tot]=w;head[u]=tot;
    to[++tot]=u;net[tot]=head[v];cap[tot]=w;head[v]=tot;
}
void spfa(int s){
    queue<int>que;
    memset(vis,0,sizeof(vis));
    memset(dis,0x3f,sizeof(dis));
    que.push(s);
    dis[s]=0;vis[s]=1;
    while(!que.empty()){
        int now=que.front();
        que.pop();
        vis[now]=0;
        for(int i=head[now];i;i=net[i])
            if(dis[to[i]]>dis[now]+cap[i]){
                dis[to[i]]=dis[now]+cap[i];
                if(!vis[to[i]]){
                    vis[to[i]]=1;
                    que.push(to[i]);
                }
            }
    }
}
int main(){
    scanf("%d",&t);
    while(t--){
        tot=0;
        memset(head,0,sizeof(head));
        scanf("%d%d",&r,&c);
        for(int i=1;i<=r;i++){
            scanf("%s",s);
            for(int j=0;j<c;j++)
                if(s[j]==‘/‘){
                    add((i-1)*(c+1)+j+2,i*(c+1)+j+1,0);
                    add((i-1)*(c+1)+j+1,i*(c+1)+j+2,1);
                }    
                else{
                    add((i-1)*(c+1)+j+1,i*(c+1)+j+2,0);
                    add((i-1)*(c+1)+j+2,i*(c+1)+j+1,1);
                }
        }
        spfa(1);
        if(dis[(r+1)*(c+1)]==0x3f3f3f3f)    cout<<"NO SOLUTION"<<endl;
        else     cout<<dis[(r+1)*(c+1)]<<endl;
    }
}

#include<queue>
#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
#define MAXN 1050010
using namespace std;
struct nond{
    int number,dis;
    bool operator < (nond b) const{
        return dis>b.dis;
    }
};
char s[1010];
int t,r,c,tot;
int dis[MAXN];
int to[MAXN*2],net[MAXN*2],cap[MAXN*2],head[MAXN*2];
void add(int u,int v,int w){
    to[++tot]=v;net[tot]=head[u];cap[tot]=w;head[u]=tot;
    to[++tot]=u;net[tot]=head[v];cap[tot]=w;head[v]=tot;
}
void dijkstra(int s){
    priority_queue<nond>que;
    memset(dis,0x3f,sizeof(dis));
    que.push((nond){s,0});
    dis[s]=0;
    while(!que.empty()){
        nond now=que.top();
        que.pop();
        if(dis[now.number]!=now.dis)    continue;
        for(int i=head[now.number];i;i=net[i])
            if(dis[to[i]]>dis[now.number]+cap[i]){
                dis[to[i]]=dis[now.number]+cap[i];
                que.push((nond){to[i],dis[to[i]]});
            }
    }
}
int main(){
    scanf("%d",&t);
    while(t--){
        tot=0;
        memset(head,0,sizeof(head));
        scanf("%d%d",&r,&c);
        for(int i=1;i<=r;i++){
            scanf("%s",s+1);
            for(int j=1;j<=c;j++)
                if(s[j]==‘/‘){
                    add((i-1)*(c+1)+j+1,i*(c+1)+j,0);
                    add((i-1)*(c+1)+j,i*(c+1)+j+1,1);
                }    
                else{
                    add((i-1)*(c+1)+j,i*(c+1)+j+1,0);
                    add((i-1)*(c+1)+j+1,i*(c+1)+j,1);
                }
        }
        dijkstra(1);
        if(dis[(r+1)*(c+1)]==0x3f3f3f3f)    cout<<"NO SOLUTION"<<endl;
        else     cout<<dis[(r+1)*(c+1)]<<endl;
    }
}