二分图匹配模板（dfs+bfs）

dfs版：

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bool dfs(int u)

{

for(int i = head[u]; ~i; i = e[i].next) {

int v = e[i].v;

if(!vis[v]) {

vis[v] = true;

if(my[v] == -1 || dfs(my[v])) {

my[v] = u;

mx[u] = v;

return true;

}

}

}

return false;

}

int hungary()

{

int ret = 0;

memset(mx, -1, sizeof(mx));

memset(my, -1, sizeof(my));

for(int i = 1; i <= X; i++) {

if(mx[i] == -1) {

memset(vis, 0, sizeof(vis));

if(dfs(i)) ret++;

}

}

return ret;

}

bfs版：

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bool bfs(int st)

{

queue <int> q;

q.push(st);

pre[st] = -1;

bool flag = false;

while(!q.empty() && !flag) {

int u = q.front(); q.pop();

for(int i = head[u]; ~i && !flag; i = e[i].next) {

int v = e[i].v;

if(vis[v] != st) {

vis[v] = st;

q.push(my[v]);

if(~my[v]) pre[my[v]] = u;

else {

int a = u, b = v;

flag = true;

while(~a) {

int t = mx[a];

mx[a] = b;

my[b] = a;

a = pre[a];

b = t;

}

}

}

}

}

return mx[st] != -1;

}

int hungary()

{

int ret = 0;

memset(mx, -1, sizeof(mx));

memset(my, -1, sizeof(my));

memset(vis, -1, sizeof(vis));

for(int i = 1; i <= nX; i++) {//number from 1

if(mx[i] == -1) {

if(bfs(i)) ret++;

}

}

return ret;

}