hdu 3572 task schedule 网络流

http://acm.hdu.edu.cn/showproblem.php?pid=3572

#include <stdio.h>
#include <string.h>
#include <algorithm>
using namespace std;

const int MAXN = 3000;
const int MAXM = 210000;
const int INF =0x7ffffff;
struct Edge
{
int st, ed;
int next;
int flow;
}edge[MAXM];
int head[MAXN];
int n,m,S,T,tot,day;

int seq[MAXM], sl;

int ans = 0;
void add_edge(int u, int v, int w)
{
edge[tot].flow = w;
edge[tot].st = u;
edge[tot].ed = v;
edge[tot].next = head[u];
head[u] = tot++;

edge[tot].flow = 0;
edge[tot].st = v;
edge[tot].ed = u;
edge[tot].next = head[v];
head[v] = tot++;
}

void Build()
{
int i,j,p,s,e;
scanf("%d%d",&n,&m);
S=0,T=500+n+1; tot=0; day=0;
memset(head,-1,sizeof(head));
for(i=1;i<=n;++i)
{
scanf("%d%d%d",&p,&s,&e);
day+=p;
add_edge(0,i,p);
for(j=s;j<=e;++j) add_edge(i,n+j,1);
}
for(i=1;i<=500;++i) add_edge(n+i,T,m);
}

//
int d[MAXN];
bool dinic_bfs()
{
int i, j;
memset(d, -1, sizeof(d));
int que[MAXN*10], rear = 1;
que[0] = S; d[S] = 0;
for(i = 0; i < rear; i++)
for(j = head[que[i]]; j != -1; j = edge[j].next)
if(d[edge[j].ed] == -1 && edge[j].flow > 0)
{
d[edge[j].ed] = d[que[i]]+1;
que[rear++] = edge[j].ed;
}
return d[T] >= 0;
}

int dinic_dfs()
{
int src=S,dest=T;
int stk[MAXN], top = 0;
int ret = 0, cur, ptr, pre[MAXN], minf, i;
bool del[MAXN];
memset(del, false, sizeof(del));

stk[top++] = src;
pre[src] = src; cur = src;
while(top)
{
while(cur != dest && top)
{
for(i = head[cur]; i != -1; i = edge[i].next)
{
if(d[edge[i].ed] == d[cur]+1 && edge[i].flow > 0 && !del[edge[i].ed])
{
stk[top++] = edge[i].ed;
cur = edge[i].ed;
pre[edge[i].ed] = i;
break;
}
}
if(i == -1)
{
del[cur] = 1;
top--;
if(top) cur = stk[top-1];
}
}
//update the flow
if(cur == dest)
{
minf = INF;
while(cur != src)
{
cur = pre[cur];
if(edge[cur].flow < minf) minf = edge[cur].flow;
cur = edge[cur].st;
}
cur = dest;
while(cur != src)
{
cur = pre[cur];
edge[cur].flow -= minf;
edge[cur^1].flow += minf;
if(edge[cur].flow == 0) ptr = edge[cur].st;
cur = edge[cur].st;
}
while(top > 0&& stk[top-1] != ptr) top--;
if(top) cur = stk[top-1];
ret += minf;
}
}
return ret;
}

int Dinic()
{
int ret = 0, t;
while(dinic_bfs())
{
t = dinic_dfs();
if(t) ret += t;
else break;
}
if(ret==day) puts("Yes\n");
else puts("No\n");
}
int main()
{
//freopen("in.txt","r",stdin);
int t;
scanf("%d",&t);
for(int i=1;i<=t;++i)
{
printf("Case %d: ",i);
Build();
Dinic();
}
return 0;
}