Smallest Minimum Cut HDU - 6214(最小割集)
Smallest Minimum Cut
Time Limit: 2000/2000 MS (Java/Others) Memory Limit: 65535/32768 K (Java/Others)
Total Submission(s): 2281 Accepted Submission(s): 913
Each case describes a network G, and the first line contains two integers n (2≤n≤200) and m (0≤m≤1000) indicating the sizes of nodes and edges. All nodes in the network are labelled from 1 to n.
The second line contains two different integers s and t (1≤s,t≤n) corresponding to the source and sink.
Each of the next m lines contains three integers u,v and w (1≤w≤255) describing a directed edge from node u to v with capacity w.
4 5
1 4
1 2 3
1 3 1
2 3 1
2 4 1
3 4 2
4 5
1 4
1 2 3
1 3 1
2 3 1
2 4 1
3 4 3
3
- #include <iostream>
- #include <cstdio>
- #include <sstream>
- #include <cstring>
- #include <map>
- #include <cctype>
- #include <set>
- #include <vector>
- #include <stack>
- #include <queue>
- #include <algorithm>
- #include <cmath>
- #define rap(i, a, n) for(int i=a; i<=n; i++)
- #define rep(i, a, n) for(int i=a; i<n; i++)
- #define lap(i, a, n) for(int i=n; i>=a; i--)
- #define lep(i, a, n) for(int i=n; i>a; i--)
- #define rd(a) scanf("%d", &a)
- #define rlld(a) scanf("%lld", &a)
- #define rc(a) scanf("%c", &a)
- #define rs(a) scanf("%s", a)
- #define MOD 2018
- #define LL long long
- #define ULL unsigned long long
- #define Pair pair<int, int>
- #define mem(a, b) memset(a, b, sizeof(a))
- #define _ ios_base::sync_with_stdio(0),cin.tie(0)
- //freopen("1.txt", "r", stdin);
- using namespace std;
- const int maxn = , INF = 0x7fffffff;
- int head[maxn], cnt;
- int d[maxn], vis[maxn], cur[maxn];
- int s, t;
- struct node
- {
- int u, v, c, next;
- }Node[maxn<<];
- void add_(int u, int v, int c)
- {
- Node[cnt].u = u;
- Node[cnt].v = v;
- Node[cnt].c = c;
- Node[cnt].next = head[u];
- head[u] = cnt++;
- }
- void add(int u, int v, int c)
- {
- add_(u, v, c);
- add_(v, u, );
- }
- void init()
- {
- mem(head, -);
- cnt = ;
- }
- bool bfs()
- {
- queue<int> Q;
- mem(d, );
- Q.push(s);
- d[s] = ;
- while(!Q.empty())
- {
- int u = Q.front(); Q.pop();
- for(int i=head[u]; i!=-; i=Node[i].next)
- {
- node e = Node[i];
- if(!d[e.v] && e.c > )
- {
- d[e.v] = d[e.u] + ;
- Q.push(e.v);
- if(e.v == t) return ;
- }
- }
- }
- return d[t] != ;
- }
- int dfs(int u, int cap)
- {
- int ret = , V;
- if(u==t || cap == )
- return cap;
- for(int &i=cur[u]; i!=-; i=Node[i].next)
- {
- node e = Node[i];
- if(d[e.v] == d[e.u] + && e.c > )
- {
- int V = dfs(e.v, min(cap, e.c));
- Node[i].c -= V;
- Node[i^].c += V;
- ret += V;
- cap -= V;
- if(cap == ) break;
- }
- }
- if(cap > ) d[u] = -;
- return ret;
- }
- int dinic(int u)
- {
- int ans = ;
- while(bfs())
- {
- memcpy(cur, head, sizeof(head));
- ans += dfs(u, INF);
- }
- return ans;
- }
- int main()
- {
- int T, n, m;
- rd(T);
- while(T--)
- {
- int u, v, c;
- init();
- rd(n); rd(m);
- rd(s), rd(t);
- rep(i, , m)
- {
- rd(u), rd(v), rd(c);
- add(u, v, c*(m+) + );
- }
- int res = dinic(s);
- cout<< res % (m+) <<endl;
- }
- return ;
- }
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