POJ

POJ - 1459

题意：看题看的心累，其实就是所有power station是源点，所有consumer是汇点，然后就是一个最大流问题了~
读入写的有点蠢，其实scanf(" ()") 这种就够啦~
另外，对于单路增广的dinic来说，当前弧优化真的很有必要。

#include <cstdio>#include <cstring>#include <algorithm>#include <iostream>#include <cmath>#include <queue>using namespace std;const int maxn = 200 + 10, maxe = maxn*maxn;const int inf = 0x3f3f3f3f;struct node{    int to,next,cap,rev;    node(){}    node(int a,int b,int c,int d){to = a; next = b; cap = c; rev = d;}}edge[maxe << 2];int num;int h[maxn],deg[maxn],cur[maxn];int n,np,nc,m;int s,t;    //源， 汇void init(){    for(int i = 0; i < maxn; i++)        h[i] = -1,deg[i]  = 0;    s = 0, t = n+1;    num = 0;}void add(int u,int v,int cap){    edge[num] = node(v,h[u],cap,num+1); h[u] = num++;    edge[num] = node(u,h[v],0,num-1);   h[v] = num++;}int bfs(){    for(int i = 0; i < maxn; i++) deg[i] = -1;    queue<int> q;    q.push(0);    deg[0] = 0;    while(!q.empty())    {        int u = q.front(); q.pop();        for(int i = h[u] ; ~i ; i = edge[i].next)        {            int v = edge[i].to,cap = edge[i].cap;            if(cap && deg[v] == -1)            {                deg[v] = deg[u] + 1;                q.push(v);            }        }    }    return deg[t] != -1;}int dfs(int u,int f){    if(u == t) return f;    for(int i = cur[u]; ~i; i = edge[i].next)    {        cur[u] = i;        int v = edge[i].to,cap = edge[i].cap, rev = edge[i].rev;        if(cap && deg[v] == deg[u] + 1)        {            int k = dfs(v,min(f,cap));            if(k == 0) continue;            edge[i].cap -= k;            edge[rev].cap += k;            return k;        }    }    return 0;}void solve(){    int flow = 0;    while(bfs())    {        for(int i = 0; i < maxn; i++)            cur[i] = h[i];        for(;;)        {            int k = dfs(0,inf);            if(k == 0) break;            flow += k;        }    }    printf("%d\n",flow);}char str[1000];void readnum(int way){    int v = 0,cap = 0;    scanf("%s",str); int slen = strlen(str);    int j;    for(j = 1; j < slen; j++)    {        if(str[j] == ')') break;        v = v*10 + str[j] - '0';    }    j++;    for(; j < slen; j++)        cap = cap*10 + str[j] - '0';    if(way) add(s,v+1,cap);    else add(v+1,t,cap);}void read(){    for(int i = 0; i < m; i++)    {        int u = 0,v = 0,cap = 0;        scanf("%s",str);        int slen = strlen(str);        int j;        for(j = 1; j < slen;j++)        {            if(str[j] == ',') break;            u = u*10 + str[j] - '0';        }        j++;        for(; j < slen; j++)        {            if(str[j] == ')') break;            v = v*10 + str[j] - '0';        }        j++;        for(; j < slen; j++)            cap = cap*10 + str[j] - '0';       // cout << u << " " << v << " " <<cap << endl;        add(u+1,v+1,cap);    }    for(int i = 0; i < np; i++)        readnum(1);    for(int i = 0; i < nc; i++)        readnum(0);}int main(){    //freopen("D:\\in.txt","r",stdin);    int a,b,c;    while(~scanf("%d",&n))    {        init();        scanf("%d%d%d",&np,&nc,&m);        read();        solve();    }    return 0;}