HDU 3572 Task Schedule

 这个题目，纠结 了很久！ 到现在还不知道自己的代码哪里RE了！  先保存下，慢慢再看吧。。

我的：

#include<iostream>
#include<algorithm>
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<queue>
#include<math.h>
#define MAXN 1210
#define INF 1<<30
using namespace std;

struct set
{
	int u,v,w,next;
}edge[503000];
int idx,n,m,s,t;
int fa[MAXN],res[MAXN],level[MAXN],gap[MAXN],head[MAXN],cur[MAXN];

int MIN(int a,int b){return a<b?a:b;}

void addedge(int u,int v,int w)
{
	edge[idx].u=u;
	edge[idx].v=v;
	edge[idx].w=w;
	edge[idx].next=head[u];
	head[u]=idx++;
	edge[idx].u=v;
	edge[idx].v=u;
	edge[idx].w=0;
	edge[idx].next=head[v];
	head[v]=idx++;
}

int retreat(int u)
{
	int id,v,min_level=t+1;
	cur[u]=head[u];
	for(id=head[u];id!=-1;id=edge[id].next)
	{
		v=edge[id].v;
		if(edge[id].w>0 && level[v]<min_level)
		{
			min_level=level[v];
			cur[u]=id;
		}
	}
	return min_level+1;
}
int sap()
{
	int id,i,u=s,v,flow=0;
	memset(level,0,sizeof(level));
	memset(gap,0,sizeof(gap));
	res[s]=INF; 
	fa[s]=-1;
	gap[0]=t+1;
	for(i=0;i<=t+1;i++)	cur[i]=head[i];
	while(level[s]<=t)
	{
		int fine=0;
		if(u==t) 
		{
			flow+=1;
			for(i=fa[u];i!=-1;i=fa[i])
			{
				id=cur[i];
				edge[id].w-=1;
				edge[id ^1].w+=1;
				res[i]-=1;
				if(edge[id].w==0) u=i;
			}
		}
		for(id=cur[u];id!=-1;id=edge[id].next)
		{
			v=edge[id].v;
			if(edge[id].w>0 && level[u]==level[v]+1)
			{
				res[v]=MIN(res[u],edge[id].w);
				fa[v]=u;
				cur[u]=id;
				u=v;
				fine=1;
				break;
			}
		}
		if(!fine)
		{
			if(--gap[level[u]]==0) return flow;
			v=retreat(u);
			level[u]=v;
			gap[v]++;
			if(u!=s) u=fa[u];
		}
	}
	return flow;
}

int main()
{
//	freopen("in.txt","r",stdin);
	int i,j,test,a,x,b;
	scanf("%d",&test);
	for(int ca=1;ca<=test;ca++)
	{
		memset(head,-1,sizeof(head));
		int idx=0,topx=0,maxb=0;
		scanf("%d%d",&n,&m);
		for(i=1;i<=n;i++)
		{
			scanf("%d%d%d",&x,&a,&b);
			if(b>maxb) maxb=b;
			topx+=x;
			addedge(0,i,x);
			for(j=n+a;j<=n+b;j++) addedge(i,j,1);
		}
		s=0;  t=maxb+n+1;
		for(i=n+1;i<=n+maxb;i++) addedge(i,t,m);
		printf("Case %d: %s\n\n",ca,(sap()==topx)?"Yes":"No");
	}
	return 0;
}

 能AC 的：

#include <iostream>
#include <cstdio>
#include <cstring>
#include <queue>
#include <algorithm>

using namespace std;

const int maxn = 1111;
const int maxm = 505000;
const int oo = 1 << 30;

int idx;
int cur[maxn], pre[maxn];
int dis[maxn], gap[maxn];
int aug[maxn], head[maxn];

struct Node
{
	int u, v, w;
	int next;
}edge[maxm];

void addEdge(int u, int v, int w)
{
    edge[idx].u = u;
    edge[idx].v = v;
    edge[idx].w = w;
    edge[idx].next = head[u];
    head[u] = idx++;

    edge[idx].u = v;
    edge[idx].v = u;
    edge[idx].w = 0;
    edge[idx].next = head[v];
    head[v] = idx++;
}


int SAP(int s, int e, int n)
{
    int max_flow = 0, v, u = s;
    int id, mindis;
    aug[s] = oo;
    pre[s] = -1;
    memset(dis, 0, sizeof(dis));
    memset(gap, 0, sizeof(gap));
    gap[0] = n; // 我觉得这一句要不要都行，因为dis[e]始终为0
    for (int i = 0; i <= n; ++i)
    {   // 初始化当前弧为第一条弧
        cur[i] = head[i];
    }

    while (dis[s] < n)
    {
        bool flag = false;
        if (u == e)
        {
            max_flow += aug[e];
            for (v = pre[e]; v != -1; v = pre[v]) // 路径回溯更新残留网络
            {
                id = cur[v];
                edge[id].w -= aug[e];
                edge[id^1].w += aug[e];
                aug[v] -= aug[e]; // 修改可增广量，以后会用到
                if (edge[id].w == 0) u = v; // 不回退到源点，仅回退到容量为0的弧的弧尾
            }
        }
        for (id = cur[u]; id != -1; id = edge[id].next)
        {   // 从当前弧开始查找允许弧
            v = edge[id].v;
            if (edge[id].w > 0 && dis[u] == dis[v] + 1) // 找到允许弧
            {
                flag = true;
                pre[v] = u;
                cur[u] = id;
                aug[v] = min(aug[u], edge[id].w);
                u = v;
                break;
            }
        }
        if (flag == false)
        {
            if (--gap[dis[u]] == 0) break; /* gap优化，层次树出现断层则结束算法 */
            mindis = n;
            cur[u] = head[u];
            for (id = head[u]; id != -1; id = edge[id].next)
            {
                v = edge[id].v;
                if (edge[id].w > 0 && dis[v] < mindis)
                {
                    mindis = dis[v];
                    cur[u] = id; // 修改标号的同时修改当前弧
                }
            }
            dis[u] = mindis + 1;
            gap[dis[u]]++;
            if (u != s) u = pre[u]; // 回溯继续寻找允许弧
        }
    }
    return max_flow;
}

int main()
{
//	freopen("in.txt","r",stdin);
    int t, n, m, pi, si, ei;
    int Max, sum, source, sink, vn;
    scanf("%d", &t);
    for (int cas = 1; cas <= t; ++cas)
    {
        idx = 0;
        memset(head, -1, sizeof(head));
        sum = 0; source = 0; Max = 0;
        scanf("%d %d", &n, &m);
        for (int i = 1; i <= n; ++i)
        {
            scanf("%d %d %d", &pi, &si, &ei);
            sum += pi;
            Max = max(Max, ei);
            addEdge(source, i, pi);
            for (int j = si; j <= ei; ++j)
            {
                addEdge(i, n + j, 1);
            }
        }
        sink = n + Max + 1;
        vn = sink + 1;
        for (int i = 1; i <= Max; ++i)
        {
            addEdge(n + i, sink, m);
        }
        if (SAP(source, sink, vn) == sum)
            printf("Case %d: Yes\n\n", cas);
        else printf("Case %d: No\n\n", cas);
    }
    return 0;
}