hdu 3991 Harry Potter and the Present II //最小路径覆盖

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很容易看出是最小路径覆盖

那场比赛几乎没怎么做，弄项目了

接着注意一些比较白痴的问题，比如将数组赋值为1<<30,接着两个相加和别人比大小。。。这是纯悲剧。。。。(TLE了N次，这里。。。悲剧)

#include <cstdio>#include <cstring>struct EDGE{    int v, next;}edge[2010010];struct NODE{    int p;    long long t;}node[1010];const long long inf = 1ll<<60;long long map[105][105];bool usedif[1005];int link[1005];int head[1010];int cnt, gx, gy;bool cmp(NODE a, NODE b){    return a.t < b.t;}void addedge(int u, int v){    edge[cnt].v = v;    edge[cnt].next = head[u];    head[u] = cnt++;}bool can(int t){    for(int p = head[t]; p != -1; p = edge[p].next)    {        int i = edge[p].v;        if(usedif[i]==0)        {            usedif[i]=1;            if(link[i]==-1||can(link[i]))            {                link[i]=t;                return true;            }        }    }    return false;}int MaxMatch(){    int num=0;    memset(link,-1,sizeof(link));    for(int i=0; i< gx; i++)    {        memset(usedif,0,sizeof(usedif));        if(can(i))  num++;    }    return num;//返回最大匹配数}int main(){    int T;    scanf("%d", &T);    int cas = 1;    while(T--)    {        int n, m, q;        scanf("%d%d%d", &n, &m, &q);        int d = 1<< 30;        for(int i = 0; i < n; i++)          for(int j = 0; j < n; j++)          if(i != j)  map[i][j] = inf;         else map[i][j] = 0;       //printf("%d\n", map[0][1]);        while(m--)        {            int a, b;            long long c;            scanf("%d%d%I64d", &a, &b, &c);            if(map[a][b] > c)            {                map[a][b] = map[b][a] = c;            }        }        for(int k = 0; k < n; k++)          for(int i = 0; i < n; i++)          {            if(i == k) continue;            if(map[i][k] == inf)  continue;            for(int j = 0; j < n; j++)            if(map[k][j] != inf && map[i][k] + map[k][j] < map[i][j])            {                map[i][j] = map[i][k] + map[k][j];            }          }        for(int i = 0; i < q; i++)        {            scanf("%d%d", &node[i].p, &node[i].t);        }        //sort(node, node + q, cmp);        gx = q;        cnt = 0;        memset(head, -1, sizeof(head));        for(int i = 0; i < q; i++)        {            for(int j = 0; j < q; j++)            if(i != j && node[j].t - node[i].t >= map[node[i].p][node[j].p])            {                //printf("%d\n",node[j].t - node[i].t);                //printf("%d\n",map[node[i].p][node[j].p]);                addedge(i, j);            }        }        //printf("cnt=%d\n", cnt);        int ans = gx - MaxMatch();        printf("Case %d: %d\n", cas++, ans - 1);    }    return 0;}