[Integration] ISAP algorithm templates for network streams and isap algorithm templates

[Integration] ISAP algorithm templates for network streams and isap algorithm templates

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# Include <iostream> # include <cstdio> # include <cstring> # include <cmath> # include <algorithm> # define MAXN 2048 # define MAXINT 0x7fffffusing namespace std; int n, m; // number of points and edge number int dis [MAXN + 1]; // distance label int num [MAXN + 1]; int src, des; // src Source point, des sink point int u, v, w; struct edge {int f; // int c of the current traffic of a certain arc; // capacity int ver; // Arc Start edge * rev; // arc edge * next; // arc end edge () {}; edge (int v, int cap, edge * nex): ver (v), c (cap), next (nex), rev (NULL), f (0) {}; void * operator new (size_t, void * p) {return p;} * s [MAXN + 1]; void init () {int queue [MAXN + 1], head = 0, tail = 0; for (int I = 1; I <= n; I ++) dis [I] = MAXN, num [I] = 0; queue [tail ++] = des; dis [des] = 0; num [0] = 1; while (head! = Tail) {int v = queue [head ++]; edge * e = s [v]; while (e) {if (e-> rev) & (e-> rev-> c = 0) | dis [e-> ver] <MAXN) {} // If the modified edge cannot pass through the stream or has been updated, you do not need to update else {dis [e-> ver] = dis [v] + 1; ++ num [dis [e-> ver]; queue [tail ++] = e-> ver;} e = e-> next ;}} int maxflow () // ISAP algorithm implementation process {int st = src, ret = 0; edge * E [MAXN], * rep [MAXN]; for (int I = 1; I <= n; I ++) E [I] = s [I]; while (dis [src] <n) // if the augmented path does not exist, stop {if (st = des) // find the augmented path {int delta = MAXINT; for (int I = src; I! = Des; I = E [I]-> ver) delta = min (delta, E [I]-> c); for (int I = src; I! = Des; I = E [I]-> ver) {E [I]-> c-= delta; E [I]-> f + = delta; E [I]-> rev-> c + = delta; E [I]-> rev-> f-= delta;} ret + = delta; st = src ;} edge * e; for (e = E [st]; e = e-> next) if (e-> c> 0 & dis [st] = dis [e-> ver] + 1) break; if (e) // The Arc {E [st] = e; rep [e-> ver] = e-> rev; st = e-> ver;} is allowed ;} else {if (-- num [dis [st]) = 0) break; // GAP optimization E [st] = s [st]; int mind = n; for (edge * t = s [st]; t = t-> next) if (t-> c> 0) mind = min (mind, dis [t-> ver]); dis [st] = mind + 1; ++ num [dis [st] ]; If (st! = Src) st = rep [st]-> ver ;}} return ret ;}int main () {freopen ("ditch. in "," r ", stdin); freopen (" ditch. out "," w ", stdout); scanf (" % d ", & m, & n); src = 1, des = n; edge * buffer = new edge [2 * m]; edge * data = buffer; while (m --) {scanf ("% d", & u, & v, & w); s [u] = new (void *) data ++) edge (v, w, s [u]); s [v] = new (void *) data ++) edge (u, 0, s [v]); s [u]-> rev = s [v]; s [v]-> rev = s [u];} init (); printf ("% d", maxflow ());}