zoukankan      html  css  js  c++  java
• # [SWUST1752] 运输问题（费用流）

题目链接：https://www.oj.swust.edu.cn/problem/show/1752

搞法如图：

```  1 #include <bits/stdc++.h>
2 using namespace std;
3
4 typedef long long LL;
5 typedef struct Node {
6     int u, v, next;
7     LL c, w;
8 }Node;
9 const int maxn = 440;
10 const int maxm = 80010;
11 const LL mod = 0x3f3f3f3fLL;
12 const LL inf = (1LL<<55);
14 LL dist[maxn];
15 LL cost, flow;
16 Node e[maxm];
17 int pre[maxn];
18 bool visit[maxn];
19 queue<int> Q;
20 int S, T, N;
21
22 void init() {
23     S = T = N = 0;
25     tot = 0;
26 }
27
28 void adde(int u, int v, LL c, LL w) {
29     e[tot].u = u; e[tot].v = v; e[tot].c = c; e[tot].w = w; e[tot].next = head[u]; head[u] = tot++;
30     e[tot].u = v; e[tot].v = u; e[tot].c = 0; e[tot].w = -w; e[tot].next = head[v]; head[v] = tot++;
31 }
32 bool spfa(int s, int t, int n) {
33     int i;
34     for(i = 0; i <= n; i++) {
35         dist[i] = inf;
36         visit[i] = 0;
37         pre[i] = -1;
38     }
39     while(!Q.empty()) Q.pop();
40     Q.push(s);
41     visit[s] = true;
42     dist[s] = 0;
43     pre[s] = -1;
44     while(!Q.empty()) {
45         int u = Q.front();
46         visit[u] = false;
47         Q.pop();
48         for(int j = head[u]; j != -1; j = e[j].next) {
49             if(e[j].c > 0 && dist[u] + e[j].w < dist[e[j].v]) {
50                 dist[e[j].v] = dist[u] + e[j].w;
51                 pre[e[j].v] = j;
52                 if(!visit[e[j].v]) {
53                     Q.push(e[j].v);
54                     visit[e[j].v] = true;
55                 }
56             }
57         }
58     }
59     if(dist[t] == inf) return false;
60     else return true;
61 }
62 LL ChangeFlow(int t) {
63     LL det = mod;
64     int u = t;
65     while(~pre[u]) {
66         u = pre[u];
67         det = min(det, e[u].c);
68         u = e[u].u;
69     }
70     u = t;
71     while(~pre[u]) {
72         u = pre[u];
73         e[u].c -= det;
74         e[u ^ 1].c += det;
75         u = e[u].u;
76     }
77     return det;
78 }
79 LL MinCostFlow(int s, int t, int n) {
80     LL mincost, maxflow;
81     mincost = maxflow = 0;
82     while(spfa(s, t, n)) {
83         LL det = ChangeFlow(t);
84         mincost += det * dist[t];
85         maxflow += det;
86     }
87     cost = mincost;
88     flow = maxflow;
89     return mincost;
90 }
91
92 int n, m;
93 int a[maxn], b[maxn], w[maxn][maxn];
94
95 int main() {
96     // freopen("in", "r", stdin);
97     while(~scanf("%d%d",&n,&m)) {
98         init();
99         S = 0, T = n + m + 1, N = T + 1;
100         for(int i = 1; i <= n; i++) scanf("%d", &a[i]);
101         for(int i = 1; i <= m; i++) scanf("%d", &b[i]);
102         for(int i = 1; i <= n; i++) {
103             for(int j = 1; j <= m; j++) {
104                 scanf("%d", &w[i][j]);
105             }
106         }
107         for(int i = 1; i <= n; i++) adde(S, i, a[i], 0);
108         for(int i = 1; i <= m; i++) adde(i+n, T, b[i], 0);
109         for(int i = 1; i <= n; i++) {
110             for(int j = 1; j <= m; j++) {
112             }
113         }
114         cout << MinCostFlow(S, T, N) << endl;
115         init();
116         S = 0, T = n + m + 1, N = T + 1;
117         for(int i = 1; i <= n; i++) adde(S, i, a[i], 0);
118         for(int i = 1; i <= m; i++) adde(i+n, T, b[i], 0);
119         for(int i = 1; i <= n; i++) {
120             for(int j = 1; j <= m; j++) {
122             }
123         }
124         cout << -MinCostFlow(S, T, N) << endl;
125     }
126     return 0;
127 }```
• 相关阅读:
流行的as3内存释放hack的方法
干掉这个网页
Flex元标签笔记Event
javascript for oop
asdoc 注释格式
怎么比较word文档，怎么比较excel文档
AS3匿名函数的this指向
SVN空间
CodeForces 315.D Sereja and Periods
Html5 filltext
• 原文地址：https://www.cnblogs.com/kirai/p/6802342.html