zoj2676 Network Wars (0-1 score plan, maximum flow template)

Network Wars

The title of the 07 Hubertau paper: http://wenku.baidu.com/view/87ecda38376baf1ffc4fad25.html
Code:

#include <algorithm> #include <cstdio> #include <iterator> #include <limits> #include < vector> #include <string.h>const int N = 111;const int M = 404;const double EPS = 1e-3;typedef std::vector<int& Gt Vi;int Signum (double x) {return x > EPS? 1: (X <-eps -1:0);}    Template<int N, int M, class flow>struct dinic {int N, E, first[n], cur[n], next[m], to[m], id[m], S, t;    int pre[n], level[n], q[n], sign;    Flow cap[m], flow;        void Add (int u, int v, Flow w, int i) {to[e] = V;        Cap[e] = W;        Id[e] = i;        Next[e] = First[u];    First[u] = e++;        } bool BFs (int s, int t) {Std::fill (level+1, Level + n + 1,-1);        sign = t;        Level[t] = 0;        int head = 0, tail = 0;        q[tail++] = t;            while (head! = Tail && level[s] = =-1) {int u = q[head++]; for (int it = First[u]; it! =-1; it = Next[it]) {if (cap[it ^ 1] > 0 &&                    Level[to[it]] = = 1) {Level[to[it]] = Level[u] + 1;                q[tail++] = To[it];    }}} return Level[s]! =-1;        } void Push () {Flow delta = Std::numeric_limits<flow>::max ();        int u, p;            for (U = t; u = s; u = to[p ^ 1]) {p = pre[u];        Delta = std::min (Delta, cap[p]);            } for (U = t; u = s; u = to[p ^ 1]) {p = pre[u];            CAP[P]-= Delta;            if (!cap[p]) {sign = to[p ^ 1];        } cap[p ^ 1] + + Delta;    } flow + + Delta;        } void Dfs (int u) {if (U = = t) {push (); } else {for (int & it = Cur[u]; it! =-1; it = Next[it]) {if (Cap[it] > 0 && le                    Vel[u] = = Level[to[it]] + 1) {Pre[to[it]] = it;                    DFS (To[it]);                       if (Level[sign] > Level[u]) { Return                } sign = t;        }} Level[u] =-1;        }} void init (int _n, int _s, int _t) {n = _n, s = _s, t = _t;        Std::fill (first + 1, first + n + 1,-1);    e = 0;        } flow Solve () {flow = 0;            while (BFS (s, t)) {for (int i = 1; I <= n; ++i) {cur[i] = First[i];        } dfs (s);    } return flow;    }};D inic<n,m<<1,double> AC; int left[m], right[m], w[m]; int N, M, Mark[m];d ouble judge (double key) {    Double sum = 0;    memset (mark, 0, sizeof (Mark));    Ac.init (n, 1, N);            for (int i = 1; I <= m; i + +) if (W[i] <= key) {sum + = w[i]-key;        Mark[i] = 1;            } else {Ac.add (left[i], right[i], W[i]-key, i);        Ac.add (Right[i], left[i], W[i]-key, i);    } Double add = Ac.solve (); Sum + = Add ; return sum;}    void Solve () {double L = 0, R = (double) m * 1E7;        while (Signum (r-l) > 0) {Double mid = (L + r)/2.0;        Double k = Judge (mid);        if (Signum (k) >= 0) L = mid;    else R = Mid;    } ac.bfs (1, N);        for (int i = 0; i < AC.E; i + +) {int u = ac.to[i^1], v = ac.to[i];    if (ac.level[u] = =-1 && ac.level[v]! =-1) mark[ac.id[i] = 1;    } int ans = 0;    for (int i = 1; I <= m; i + +) if (Mark[i]) ans + +;    printf ("%d\n", ans);    for (int i = 1; I <= m; i + +) if (Mark[i]) printf ("%d", I); Puts ("");}    int main () {//Freopen ("Network.in", "R", stdin);//Freopen ("Network.out", "w", stdout);    int flag = 0; while (scanf ("%d%d", &n, &m)! = EOF) {for (int i = 1; I <= m; i + +) scanf ("%d%d        %d ", &left[i], &right[i], &w[i]);        if (flag) puts (""); Flag =1;    Solve (); } return 0;}

zoj2676 Network Wars (0-1 score plan, maximum flow template)