bzoj2127 分类： bzoj templates 2015-08-07 16:33 14人阅读 评论(0) 收藏

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最小割，差异代价模型。

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

const int maxn = 105, maxm = 105;
const int noden = 10005, size = 4e5+5;
const int Nya = -1, INF = 0x3f3f3f3f;

template<class Num>void read(Num &x)
{
    char c; int flag = 1;
    while((c = getchar()) < '0' || c > '9')
        if(c == '-') flag *= -1;
    x = c - '0';
    while((c = getchar()) >= '0' && c <= '9')
        x = (x<<3) + (x<<1) + (c-'0');
    x *= flag;
    return;
}
template<class Num>void write(Num x)
{
    if(x < 0) putchar('-'), x = -x;
    static char s[20];int sl = 0;
    while(x) s[sl++] = x%10 + '0',x /= 10;
    if(!sl) {putchar('0');return;}
    while(sl) putchar(s[--sl]);
}

int n, m, num[maxn][maxm], ans;
int W[maxn][maxm], L[maxn][maxm];
int WR[maxn][maxm], WC[maxn][maxm];
int LR[maxn][maxm], LC[maxn][maxm];
int WT[maxn][maxm], LT[maxn][maxm];


void init()
{
    std::cin >> n >> m;
    for(int i = 1; i <= n; i++)
        for(int j = 1; j <= m; j++)
        {
            read(W[i][j]), ans += W[i][j];
            WT[i][j] += W[i][j]<<1;
        }
    for(int i = 1; i <= n; i++)
        for(int j = 1; j <= m; j++)
        {
            read(L[i][j]), ans += L[i][j];
            LT[i][j] += L[i][j]<<1;
        }
    for(int i = 1; i < n; i++)
        for(int j = 1; j <= m; j++)
        {
            read(WR[i][j]), ans += WR[i][j];
            WT[i][j] += WR[i][j], WT[i+1][j] += WR[i][j];
        }
    for(int i = 1; i < n; i++)
        for(int j = 1; j <= m; j++)
        {
            read(LR[i][j]), ans += LR[i][j];
            LT[i][j] += LR[i][j], LT[i+1][j] += LR[i][j];
        }
    for(int i = 1; i <= n; i++)
        for(int j = 1; j < m; j++)
        {
            read(WC[i][j]), ans += WC[i][j];
            WT[i][j] += WC[i][j], WT[i][j+1] += WC[i][j];
        }
    for(int i = 1; i <= n; i++)
        for(int j = 1; j < m; j++)
        {
            read(LC[i][j]), ans += LC[i][j];
            LT[i][j] += LC[i][j], LT[i][j+1] += LC[i][j];
        }
    for(int i = 1; i <= n; i++)
        for(int j = 1; j <= m; j++)
            num[i][j] = (i-1)*m+j;       
}


struct FlowEdge
{
    int v, cap, next;
    FlowEdge(int v=0,int cap=0,int next=0):v(v),cap(cap),next(next){}
}edge[size];


int head[noden], el, ind, S, T;

void NewEdge(int u,int v,int cap)
{
    edge[el] = FlowEdge(v,cap,head[u]), head[u] = el++;
    edge[el] = FlowEdge(u, 0,head[v]), head[v] = el++;
}

struct Dinic
{
    int dep[noden], cur[noden];
    std::queue<int>line;

    void build()
    {
        ind = n*m, S = ++ind, T = ++ind;

        for(int i = 1; i <= ind; i++) head[i] = Nya;

        for(int i = 1; i < n; i++)
            for(int j = 1; j <= m; j++)
            {
                NewEdge(num[i][j], num[i+1][j], WR[i][j] + LR[i][j]);
                NewEdge(num[i+1][j], num[i][j], WR[i][j] + LR[i][j]);
            }
        for(int i = 1; i <= n; i++)
            for(int j = 1; j < m; j++)
            {
                NewEdge(num[i][j], num[i][j+1], WC[i][j] + LC[i][j]);
                NewEdge(num[i][j+1], num[i][j], WC[i][j] + LC[i][j]);
            }
       for(int i = 1; i <= n; i++)
            for(int j = 1; j <= m; j++)
            {
                NewEdge(S, num[i][j], WT[i][j]);
                NewEdge(num[i][j], T, LT[i][j]);
            }
    }
    bool BFS()
    {
        for(int i = 1; i <= ind; i++) dep[i] = 0;

        dep[S] = 1, line.push(S);

        while(!line.empty())
        {
            int now = line.front(); line.pop();

            for(int i = head[now], p; i != Nya ; i = edge[i].next)
                if(edge[i].cap && !dep[p = edge[i].v])
                    dep[p] = dep[now] + 1, line.push(p);
        }

        if(dep[T])
        {
            for(int i = 1; i <= ind; i++)
                cur[i] = head[i];
            return true;    
        }
        else
            return false;
    }
    int DFS(int a,int flow)
    {
        if(a == T)return flow;

        int ret = 0;

        for(int i = cur[a], p; i != Nya; i = edge[i].next)
            if(dep[p = edge[i].v] == dep[a] + 1 && edge[i].cap)
            {
                int ff = DFS(p, std::min(flow,edge[i].cap));

                flow -= ff, edge[i].cap -= ff;
                ret += ff, edge[i^1].cap += ff;

                if(!flow)
                {
                    cur[a] = i;
                    return ret;
                }
            }

            cur[a] = Nya;        
            return ret;
    }
    int main()
    {
        int totflow = 0;

        while(true)
        {
            if(BFS() == false) break;
            totflow += DFS(S, INF);
        }

        return totflow;
    }
}dinic = {0};

int main()
{
#ifndef ONLINE_JUDGE
    freopen("bzoj2127.in","r",stdin);
    freopen("bzoj2127.out","w",stdout);
#endif          

    init(), dinic.build();

    ans -= dinic.main()>>1;

    std::cout << ans;

#ifndef ONLINE_JUDGE   
    fclose(stdin);
    fclose(stdout);
#endif
    return 0;
}

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