分配问题 【网络流24题】

  1 #include <bits/stdc++.h>
  2 #define dbg(x) cout << #x << "=" << x << endl
  3 #define eps 1e-8
  4 #define pi acos(-1.0)
  5 
  6 using namespace std;
  7 typedef long long LL;
  8 const int maxn = 1e5 +7;
  9 const int inf  = 0x3f3f3f3f;
 10 
 11 int n, m, s, t;
 12 int head[maxn],pre[maxn],inq[maxn],dis[maxn];
 13 int a[maxn];
 14 int cnt = 1;
 15 int path[2][maxn];
 16 int mincost = 0, maxflow = 0;
 17 struct edge {
 18     int u,to,nxt,w,c;
 19 }e[maxn << 1];
 20 int tot[5];
 21 
 22 template<class T>inline void read(T &res)
 23 {
 24     char c;T flag=1;
 25     while((c=getchar())<'0'||c>'9')if(c=='-')flag=-1;res=c-'0';
 26     while((c=getchar())>='0'&&c<='9')res=res*10+c-'0';res*=flag;
 27 }
 28 
 29 inline void BuildGraph(int u, int v, int w, int cost)
 30 {
 31     e[++cnt] = (edge){u, v, head[u], w,  cost}, head[u] = cnt;
 32     e[++cnt] = (edge){v, u, head[v], 0, -cost}, head[v] = cnt;///反向边
 33 }
 34 
 35 queue<int> q;
 36 
 37 inline void init() {
 38     memset(head, 0, sizeof(head));
 39     memset(pre, 0, sizeof(pre));
 40     memset(inq, 0, sizeof(inq));
 41     memset(dis, 0, sizeof(dis));
 42     memset(e, 0, sizeof(e));
 43     while(!q.empty()) {
 44         q.pop();
 45     }
 46     mincost = maxflow = 0;
 47     cnt = 1;
 48 }
 49 
 50 bool SPFA(int x)
 51 {
 52     memset(inq, 0, sizeof(inq));
 53     for(int i = s; i <= t; i++) {
 54         dis[i] = inf;
 55     }
 56     q.push(x);
 57     dis[x] = 0;
 58     inq[x] = 1;
 59     while(!q.empty()) {
 60         int u = q.front();
 61         q.pop();
 62         inq[u] = 0;
 63         for(int i = head[u]; i; i = e[i].nxt) {
 64             int v = e[i].to, w = e[i].c;
 65             if(e[i].w > 0) {
 66                 if(dis[u] + w < dis[v]) {
 67                     dis[v] = dis[u] + w;
 68                     pre[v] = i;
 69                     if(!inq[v]) {
 70                         q.push(v);
 71                         inq[v] = 1;
 72                     }
 73                 }
 74             }
 75         }
 76     }
 77     if(dis[t] == inf)
 78         return 0;
 79     return 1;
 80 }
 81 
 82 void MCMF()
 83 {
 84     while(SPFA(s)) {
 85         int temp = inf;
 86         for(int i = pre[t]; i; i = pre[e[i].u]) {
 87             temp = min(temp, e[i].w);
 88         }
 89         for(int i = pre[t]; i; i = pre[e[i].u]) {
 90             e[i].w   -= temp;
 91             e[i^1].w += temp;
 92             mincost += e[i].c * temp;
 93             //printf("e[%d].c:%d\n",i, e[i].c);
 94             //printf("ans:%d\n",ans);
 95         }
 96         //maxflow += temp;
 97     }
 98 }
 99 
100 int xx[107][107];
101 
102 int main()
103 {
104     //freopen("data.txt", "r", stdin);
105     read(n);
106     s = 0, t = n << 1 | 1;
107     for ( int i = 1; i <= n; ++i ) {
108         BuildGraph(s, i, 1, 0);
109         for ( int j = 1; j <= n; ++j ) {
110             read(xx[i][j]);
111             BuildGraph(i, j + n, 1, xx[i][j]);
112         }
113         BuildGraph(i + n, t, 1, 0);
114     }
115     MCMF();
116     int ans = mincost;
117     cout << ans << endl;
118     //dbg(maxflow);
119     init();
120     s = 0, t = n << 1 | 1;
121     for ( int i = 1; i <= n; ++i ) {
122         BuildGraph(s, i, 1, 0);
123         for ( int j = 1; j <= n; ++j ) {
124             BuildGraph(i, j + n, 1, -xx[i][j]);
125         }
126         BuildGraph(i + n, t, 1, 0);
127     }
128     MCMF();
129     ans = -mincost;
130     cout << ans << endl;
131     //dbg(maxflow);
132     return 0;
133 }