51Nod 1445（考建图的最短路）

N只有50，跑一下N的平方建图，两种颜色之间的距离就是 他前面的Y的数量，剩下的就是模板了。

#include<cstdio>#include<cstring>#include<algorithm>#include<iostream>#include<set>#include<queue>using namespace std;typedef long long ll;typedef pair<int,int > P;const int maxn = 55;const int inf = 1<<20;int n;char bmap[maxn][maxn] ;int  edge[maxn][maxn];int dist[maxn];struct node{    int id;    int dist;    bool operator < (const node& T) const{        return dist>T.dist;    }    node(int a,int b):id(a),dist(b){}};void dij(){    for(int i=0;i<n;i++) dist[i] = inf;    priority_queue<node>q;    q.push(node(0,0)); dist[0] = 0;    while(!q.empty())    {        node fr = q.top(); q.pop();        int u = fr.id;        //printf("%d\n",u);        for(int i=0;i<n;i++)        {            if(dist[i]>dist[u]+edge[u][i])            {                //printf("sdfsdfsdfsdfsd\n");                dist[i] = dist[u] + edge[u][i];                q.push(node(i,dist[i]));            }        }    }    if(dist[n-1]>=inf) printf("-1\n");    else printf("%d\n",dist[n-1]);}int main(){    int cases;    scanf("%d",&cases);    while(cases--)    {        scanf("%d",&n);        for(int i=0;i<n;i++) scanf("%s",bmap[i]);        for(int i=0;i<n;i++)        {            int sum = 0;            for(int j=0;j<n;j++)            {                if(bmap[i][j]=='N') {edge[i][j] = inf; continue;}                edge[i][j] = sum++;            }        }        dij();    }    return 0;}