POJ 2516 Minimum Cost k次费用流

#include<stdio.h>
#include<string.h>
#include<algorithm>
#include<queue>
using namespace std;
#define maxn 110
#define maxm 6000
#define inf 1000000000
int min(int a, int b)
{
    return a < b ? a : b;
}

struct E
{
    int u, v, next, c, w;
}edge[maxm<<2];

int head[maxn], tot;
int n, m, k;
int S, T;
int sum[55];

void add(int s, int t, int c, int w)
{
    edge[tot].u = s;
    edge[tot].v = t;
    edge[tot].c = c;
    edge[tot].w = w;
    edge[tot].next = head[s];
    head[s] = tot++;

    edge[tot].u = t;
    edge[tot].v = s;
    edge[tot].c = 0;
    edge[tot].w = -w;
    edge[tot].next = head[t];
    head[t] = tot++;
}

void init()
{
    tot = 0;
    memset(head, -1, sizeof(head));
}

int pre[maxn];
int dis[maxn];
bool vis[maxn];
bool spfa(int s, int t, int n)
{
    int i, u, v;
    for(i = 0; i <= n; i++)
        dis[i] = inf, pre[i] = -1, vis[i] = 0;
    queue<int> q;
    vis[s] = 1; dis[s] = 0; q.push(s);
    while(!q.empty())
    {
        u = q.front(); q.pop(); vis[u] = 0;
        for(i = head[u]; i != -1; i = edge[i].next)
        {
            v = edge[i].v;
            if(edge[i].c && dis[v] > dis[u] + edge[i].w)
            {
                dis[v] = dis[u] + edge[i].w;
                pre[v] = i;
                if(!vis[v])
                {
                    vis[v] = 1;
                    q.push(v);
                }
            }
        }
    }
    if(dis[t] == inf) return 0;
    return 1;
}

int ans, maxf;
int mfmw(int s, int t, int n)
{
    int aug, minw = 0, i;
    maxf = 0;
    while(spfa(s, t, n))
    {
        aug = inf + 1;
        for(i = pre[t]; i != -1; i = pre[edge[i].u])
            aug = min(aug, edge[i].c);
        for(i = pre[t] ;i != -1; i = pre[edge[i].u])
        {
            edge[i].c -= aug;
            edge[i^1].c += aug;
        }
        maxf += aug;
        minw += dis[t] * aug;
    }
    return minw;
}

char map[55][55][55], a[55][55], b[55][55];
int main()
{
    int i, j, u;
    int x, y, z;
    while( ~scanf("%d%d%d", &n, &m, &k))
    {
        if(!m && !n && !k) break;
        maxf = ans = 0;
        memset(sum, 0, sizeof(sum));
        for(i = 1; i <= n; i++)
            for(j = 1; j <= k; j++)
                scanf("%d", &a[i][j]), sum[j] += a[i][j];
        for(i = 1; i <= m; i++)
            for(j = 1; j <= k; j++)
                scanf("%d", &b[i][j]);
        S = 0; T = n+m+1;
        bool flag = 1;
        for(u = 1; u <= k; u++)
        {
            init();
            for(i = 1; i <= n; i++)
                for(j = 1; j <= m; j++)
                {
                    scanf("%d", &z);
                    add(j+n, i, inf, z);
                }
            if(!flag) continue;
            for(i = 1; i <= m; i++)
                add(S, i+n, b[i][u], 0);
            for(i = 1; i <= n; i++)
                add(i, T, a[i][u], 0);
            int pp = mfmw(S, T, T+1);
            if(maxf != sum[u]) flag = 0;
            ans += pp;
        }
        if(flag) printf("%d\n", ans);
        else puts("-1");
    }
    return 0;
}