NIT: 初始化邻接矩阵g[][]；| CALL: res = mincut(n)；

INIT: 初始化邻接矩阵 g[][];

| CALL: res = mincut(n);

| 注 : Stoer-Wagner Minimum Cut;

| 找边的最小集合，若其被删去则图变得不连通（我们把这种形式称为最小

| 割问题）

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#define typec int // type of res

const typec inf = 0x3f3f3f3f; // max of res

const typec maxw = 1000; // maximum edge weight

typec g[V][V], w[V];

int a[V], v[V], na[V];

typec mincut( int n){

int i, j, pv, zj;

typec best = maxw * n * n;

for (i = 0; i < n; i++) v[i] = i; // vertex: 0 ~ n-1

while (n > 1) {

for (a[v[0]] = 1, i = 1; i < n; i++) {

a[v[i]] = 0; na[i - 1] = i;

w[i] = g[v[0]][v[i]];

}

for (pv = v[0], i = 1; i < n; i++ ) {

for (zj = -1, j = 1; j < n; j++ )

if (!a[v[j]] && (zj < 0 || w[j] > w[zj]))

zj = j;

a[v[zj]] = 1;

if (i == n - 1) {

if (best > w[zj]) best = w[zj];

for (i = 0; i < n; i++)

g[v[i]][pv] = g[pv][v[i]] +=

g[v[zj]][v[i]];

v[zj] = v[--n];

break ;

}

pv = v[zj];

for (j = 1; j < n; j++) if (!a[v[j]])

w[j] += g[v[zj]][v[j]];

}

}

return best;

}