版权声明：https://blog.csdn.net/qq_41730082 https://blog.csdn.net/qq_41730082/article/details/88697643
题目链接
为了让每个不同地方来的代表都分开来，所以我们要这么建边，从起点到每个代表都是建一条边权为人数的路径，然后再由代表出发，对每个餐桌建立边权为1的流，再由餐桌链接上汇点，此时的流是餐桌的容纳人数。
#include <iostream>
#include <cstdio>
#include <cmath>
#include <string>
#include <cstring>
#include <algorithm>
#include <limits>
#include <vector>
#include <stack>
#include <queue>
#include <set>
#include <map>
#define lowbit(x) ( x&(-x) )
#define pi 3.141592653589793
#define e 2.718281828459045
#define INF 0x3f3f3f3f
#define HalF (l + r)>>1
#define lsn rt<<1
#define rsn rt<<1|1
#define Lson lsn, l, mid
#define Rson rsn, mid+1, r
#define QL Lson, ql, qr
#define QR Rson, ql, qr
#define myself rt, l, r
using namespace std;
typedef unsigned long long ull;
typedef long long ll;
const int maxE = 81555, maxN = 427;
const int S = 0;
int M, N, T, head[maxN], cur[maxN], cnt;
struct Eddge
{
int nex, to, val;
Eddge(int a=-1, int b=0, int c=0):nex(a), to(b), val(c) {}
}edge[maxE];
inline void addEddge(int u, int v, int val)
{
edge[cnt] = Eddge(head[u], v, val);
head[u] = cnt++;
}
int deep[maxN];
queue<int> Q;
bool bfs()
{
while(!Q.empty()) Q.pop(); memset(deep, 0, sizeof(deep)); deep[S] = 1; Q.push(S);
while(!Q.empty())
{
int u = Q.front(); Q.pop();
for(int i=head[u], v, val; ~i; i=edge[i].nex)
{
v = edge[i].to; val = edge[i].val;
if(!deep[v] && val)
{
deep[v] = deep[u] + 1;
Q.push(v);
}
}
}
return deep[T];
}
int dfs(int u, int flow)
{
if(u == T) return flow;
for(int &i=cur[u], v, val; ~i; i=edge[i].nex)
{
v = edge[i].to; val = edge[i].val;
if(deep[v] == deep[u] + 1 && val)
{
int di = dfs(v, min(val, flow));
if(di)
{
edge[i].val -= di;
edge[i^1].val += di;
return di;
}
}
}
return 0;
}
int Dinic()
{
int ans = 0, tmp = 0;
while(bfs())
{
for(int i=S; i<=T; i++) cur[i] = head[i];
while((tmp = dfs(S, INF))) ans += tmp;
}
return ans;
}
inline void init()
{
cnt = 0; T = N + M + 1;
memset(head, -1, sizeof(head));
}
int main()
{
scanf("%d%d", &M, &N);
init();
int all = 0;
for(int i=1, person; i<=M; i++) //每个代表的人数
{
scanf("%d", &person); all += person;
addEddge(S, i, person);
addEddge(i, S, 0);
for(int j=1; j<=N; j++)
{
addEddge(i, j + M, 1);
addEddge(j + M, i, 0);
}
}
for(int i=1, V; i<=N; i++)
{
scanf("%d", &V);
addEddge(i + M, T, V);
addEddge(T, i + M, 0);
}
bool flag = Dinic() == all;
printf("%d\n", flag);
if(!flag) return 0;
for(int u=1; u<=M; u++)
{
for(int i=head[u], v, val; ~i; i=edge[i].nex)
{
v = edge[i].to; val = edge[i^1].val;
if(v > S && v < T && val) printf("%d ", v - M);
}
printf("\n");
}
return 0;
}