zoj3509 Island Communication

http://acm.zju.edu.cn/onlinejudge/showProblem.do?problemId=4352

有题解给的是动态树 http://hi.baidu.com/xpycc/item/0e5b0feb827e203a86d9de92

 

自己一顿乱搞，双向链表 。

#include <cstdio>#include <iostream>#include <cstring>#include <map>#include <string>#include <algorithm>#include <map>#include <queue>using namespace std;const int inf = 0x7fffffff;const int maxm=50000+123;const int maxn=555;struct Edge{    int v, next, pre;}edge[maxm<<2];int cnt, head[maxn];int Map[maxn][maxn];int D[maxn][maxn];///char ops[maxm];int x[maxm], y[maxm];void addedge(int u, int v){    edge[cnt].v=v;    edge[cnt].next=head[u];    edge[cnt].pre=-1;    if(~head[u])edge[head[u]].pre=cnt;    Map[u][v]=cnt;    head[u]=cnt++;    edge[cnt].v=u;    edge[cnt].next=head[v];    edge[cnt].pre=-1;    if(~head[v])edge[head[v]].pre=cnt;    Map[v][u]=cnt;    head[v]=cnt++;}void deledge(int u, int v){    int p1=Map[u][v], p2=Map[v][u];    if(p1 == -1 || p2 == -1) return;///边已经不存在了    Map[u][v]=Map[v][u]=-1;    if(~edge[p1].pre)edge[edge[p1].pre].next=edge[p1].next;    else head[u]=edge[p1].next;    if(~edge[p1].next)edge[edge[p1].next].pre=edge[p1].pre;    if(~edge[p2].pre)edge[edge[p2].pre].next=edge[p2].next;    else head[v]=edge[p2].next;    if(~edge[p2].next)edge[edge[p2].next].pre=edge[p2].pre;}void init(int n){    cnt=0;    memset (head, -1, sizeof(int)*(n+5));    memset (Map, -1, sizeof(Map));    for (int i=0; i<=n; ++i)        for (int j=0; j<=n; ++j)            D[i][j]=inf;}void debug(int n){    for (int i=1; i<=n; ++i)    {        printf("%d:", i);        for (int p=head[i]; ~p; p=edge[p].next)        {            printf("->v=%d", edge[p].v);        }        puts("");    }}bool dfs(int u, int fa, int &dm, const int &to){    //printf("%d %d\n", u, fa);    if(u==to)return true;    for (int p=head[u]; ~p; p=edge[p].next)    {        if(edge[p].v==fa)continue;        if(dfs(edge[p].v, u, dm, to))        {            dm=min(dm, D[u][edge[p].v]);            return true;        }    }    return false;}int main (){    int n, m;    int T=0;    while (~scanf("%d%d", &n, &m))    {        init(n);        if(T)puts("");        printf("Case %d:\n", ++T);        for (int i=0; i<m; ++i)        {            scanf("%s %d %d", ops+i, x+i, y+i);            if(ops[i]=='D')            {                D[x[i]][y[i]]=D[y[i]][x[i]]=i;            }        }        for (int i=0; i<m; ++i)        {            if(ops[i]=='I')            {                int dm=inf;                if(dfs(x[i], -1, dm, y[i]))                {                    if(dm<D[x[i]][y[i]])                    {                        addedge(x[i], y[i]);                        deledge(x[dm], y[dm]);                    }                }                else                    addedge(x[i], y[i]);            }            if(ops[i]=='D' )            {                deledge(x[i], y[i]);            }            if(ops[i]=='Q')            {                int dm=inf;                puts(dfs(x[i], -1, dm, y[i])?"YES":"NO");            }//            printf("op:  %d %c %d %d\n", i, ops[i], x[i], y[i]);//            debug(n);        }    }    return 0;}/*5 9I 1 2I 2 3Q 1 3I 2 4I 1 3I 4 5D 1 2D 2 3Q 1 55 10I 1 2I 2 3Q 1 3I 1 3I 2 4I 4 5D 1 2D 2 3Q 1 5Q 2 43 6I 1 2I 2 3I 3 1D 1 2D 2 3Q 1 2*/