Network Flow (iii)----maximum stream SAP algorithm

Template with HDU 3572 Task Schedule as an example

Code:

#include <cstdio> #include <cstdlib> #include <cstring> #include <cctype> #include <cmath > #include <algorithm> #include <vector> #include <queue> #include <stack> #include <map >using namespace Std;const int inf = 0x3f;const int inf = 0x3f3f3f3f;const int MAXN = 40002;struct node{int to, Flo W, Next;} EDGE[MAXN * 8];int N, m;int S, T;int tot;int q[maxn];int DIS[MAXN], PRE[MAXN], REC[MAXN], Head[maxn];int GAP[MAXN], Cur[ma    xn];inline void Add_edge (int a, int b, int c) {edge[tot].to = b; edge[tot].flow = c; edge[tot].next = Head[a];    Head[a] = tot++; Edge[tot].to = A; Edge[tot].flow = 0;    Edge[tot].next = Head[b]; HEAD[B] = tot++;}     void Init () {tot = 0; Memset (Head,-1, sizeof (head));}     void BFS () {int i;    int h = 0, t = 0;    for (i = 0; I <= T; i++) dis[i] = INF;    Q[H] = T;    Dis[t] = 0;        while (H <= t) {int u = q[h++];        gap[dis[u]]++;    for (i = head[u]; I! =-1; i = edge[i].next)    {int v = edge[i].to;                if (dis[v] = = INF && edge[i^1].flow) {Dis[v] = Dis[u] + 1;            Q[++t] = v;    }}}}int SAP () {int i;    int u = pre[s] = S, Maxflow = 0, flow = INF;        for (i = 0; I <= t; i++)//Here T is the maximum vertex number {Gap[i] = 0;    Cur[i] = Head[i];    } BFS ();            while (Dis[s] <= t) {if (U = = t) {maxflow + = flow;                for (; U! = S; u = pre[u]) {edge[rec[u]].flow-= flow;            Edge[rec[u]^1].flow + = flow;        } flow = INF;            } for (i = cur[u]; I! =-1; i = edge[i].next) {int v = edge[i].to;                if (Edge[i].flow && dis[u] = = Dis[v] + 1) {flow = min (flow, edge[i].flow);                PRE[V] = u;                REC[V] = i;                Cur[u] = i;//current arc optimized u = V;            Break        }} if (i = =-1) {int Mindis = T + 1;//t is vertex number if ((--gap[dis[u]) = = 0) break;//clearance optimization for (i = cur[u] = Head[u]; I! =-1; i = edge[i].next) {if (Edge[i].flow && Mindis & Gt                Dis[edge[i].to]) {Mindis = dis[edge[i].to];            }} Gap[dis[u] = mindis+1]++;        U = pre[u]; }} return maxflow;}    int main () {int ncase,n,m;    scanf ("%d", &ncase);        for (int kase = 1;kase <= ncase;kase++) {Init ();        scanf ("%d%d", &n,&m);        S = 0,t = 1001;        int sum = 0;            for (int i = 1;i <= n;i++) {int start,process,end;            scanf ("%d%d%d", &process,&start,&end);            sum + = process;            Add_edge (s,i,process);        for (int j = start;j <= end;j++) Add_edge (i,500+j,1); } for (int i = 501;i <= 1000;i++) Add_edge (i,t,m);       BOOL flag = TRUE;        int tmp = SAP ();        printf ("TMP =%d\n", TMP);        if (tmp! = SUM) flag = false;        printf ("Case%d:", Kase);        if (flag) printf ("yes\n\n");    else printf ("no\n\n"); } return 0;}

　　

Network Flow (iii)----maximum stream SAP algorithm