poj 1459 Power Network

来源：互联网发布：为什么不能下载java 编辑：程序博客网时间：2024/06/08 12:39
原题链接：http://poj.org/problem?id=1459
Dinic求最大流。。
#include<algorithm>#include<iostream>#include<cstdlib>#include<cstring>#include<cstdio>#include<vector>#include<queue>#include<map>using std::min;using std::find;using std::sort;using std::pair;using std::queue;using std::vector;using std::multimap;#define pb(e) push_back(e)#define sz(c) (int)(c).size()#define mp(a, b) make_pair(a, b)#define all(c) (c).begin(), (c).end()#define iter(c) __typeof((c).begin())#define cls(arr, val) memset(arr, val, sizeof(arr))#define cpresent(c, e) (find(all(c), (e)) != (c).end())#define rep(i, n) for(int i = 0; i < (int)n; i++)#define tr(c, i) for(iter(c) i = (c).begin(); i != (c).end(); ++i)const int N = 210;const int INF = 0x3f3f3f3f;struct Dinic {    struct edge { int to, cap, next, rev; }G[(N * N) << 1];    int s, t, tot, level[N], ite[N], head[N];    inline void init() {        tot = 0, cls(head, -1);    }    inline void add_edge(int u, int v, int cap) {        G[tot] = (edge){ v, cap, head[u], tot + 1 }; head[u] = tot++;        G[tot] = (edge){ u,   0, head[v], tot - 1 }; head[v] = tot++;    }    inline void built(int n, int np, int nc, int m) {        int u, v, f;        s = 0, t = n + 1;        rep(i, m) {            scanf(" (%d,%d)%d", &u, &v, &f);            add_edge(u + 1, v + 1, f);        }        rep(i, np) {            scanf(" (%d)%d", &v, &f);            add_edge(s, v + 1, f);        }        rep(i, nc) {            scanf(" (%d)%d", &u, &f);            add_edge(u + 1, t, f);        }    }    inline void bfs(int s) {        cls(level, -1);        queue<int> q;        q.push(s);        level[s] = 0;        while(!q.empty()) {            int u = q.front(); q.pop();            for(int i = head[u]; ~i; i = G[i].next) {                edge &e = G[i];                if(e.cap > 0 && level[e.to] < 0) {                    level[e.to] = level[u] + 1;                    q.push(e.to);                }            }        }    }    inline int dfs(int u, int t, int f) {        if(u == t) return f;        for(int &i = ite[u]; ~i; i = G[i].next) {            edge &e = G[i];            if(e.cap > 0 && level[u] < level[e.to]) {                int d = dfs(e.to, t, min(e.cap, f));                if(d > 0) {                    e.cap -= d;                    G[e.rev].cap += d;                    return d;                }            }        }        return 0;    }    inline int max_flow() {        int flow = 0;        while(true) {            bfs(s);            if(level[t] < 0) break;            int f;            rep(i, t) ite[i] = head[i];            while((f = dfs(s, t, INF)) > 0) {                flow += f;            }        }        return flow;    }    inline void solve(int n, int np, int nc, int m) {        init(), built(n, np, nc, m);        printf("%d\n", max_flow());    }}go;int main() {#ifdef LOCAL    freopen("in.txt", "r", stdin);    freopen("out.txt", "w+", stdout);#endif    int n, np, nc, m;    while(~scanf("%d %d %d %d", &n, &np, &nc, &m)) {        go.solve(n, np, nc, m);    }    return 0;}
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