建图方式：

S->同意 ,反对->T

对于每一对好友连容量为1的边

#include 
    
     using namespace std;const int inf = 1e9;const int MAXN = 3e2+7;const int MAXM = 2e5+7;int n, m, s, t, dep[MAXN], maxflow;struct Edge {    int v, w, next;} G[MAXM];int tot = 1, head[MAXN], cur[MAXN];inline void add(int u, int v, int w) {    G[++tot].v=v, G[tot].w=w, G[tot].next=head[u];    head[u]=tot;} bool bfs(int s, int t) {    memset(dep, 0x7f, sizeof dep);    memcpy(cur+1, head+1, n*4+8);    queue
     
      q;    while(!q.empty()) q.pop();    dep[s] = 0;    q.push(s);    while(!q.empty()) {        int u = q.front();        q.pop();        for(int i = head[u]; i; i = G[i].next) {            int v = G[i].v, w = G[i].w;            if (dep[v] > inf && w) {                dep[v] = dep[u] + 1;                if (v == t) return 1;                q.push(v);            }        }    }    return dep[t] < inf;} int dfs(int u, int t, int limit) {    if (u == t || !limit) return limit;    int flow = 0, f;    for(int i = cur[u]; i; i = G[i].next) {        cur[u] = i;        int v = G[i].v, w = G[i].w;        if (dep[v] == dep[u] + 1 && (f = dfs(v, t, min(w, limit)))) {            flow += f;            limit -= f;            G[i].w -= f;            G[i^1].w += f;            if (!limit) break;        }    }    return flow;} void dinic(int s, int t) {    while(bfs(s, t)) maxflow += dfs(s, t, inf);} int main(void) {    // memset(head, -1, sizeof head);    scanf("%d%d", &n, &m);    for(int i = 1; i <= n; ++i) {        scanf("%d", &s);        if (s) add(n+1, i, 1), add(i, n+1, 0);        else add(i, n+2, 1), add(n+2, i, 0);    }    for(int i = 1; i <= m; ++i) {        int u, v;        scanf("%d%d", &u, &v);        add(u, v, 1), add(v, u, 1);//      add(u, v, 0), add(v, u, 0);//加不加都行，因为不会退流    }    dinic(n+1, n+2);    printf("%d", maxflow);    return 0;}