题目链接：https://www.luogu.org/problemnew/show/P2071#sub
邻接表 + 匈牙利
把之前的邻接矩阵匈牙利变成邻接表
要不然存不下...
code：
1 #include <iostream> 2 #include <cstdio> 3 #include <algorithm> 4 #include <cstring> 5 using namespace std; 6 inline int read() 7 { 8 int ret=0; 9 char c=getchar(); 10 while (c<'0' || c>'9') c=getchar(); 11 while (c>='0' && c<='9'){ 12 ret=((ret<<3)+(ret<<1))+c-'0'; 13 c=getchar(); 14 } 15 return ret; 16 } 17 const int maxn = 4010; 18 int n, ans, cnt; 19 int link[maxn], head[maxn]; 20 bool vis[maxn]; 21 struct edge{ 22 int v,next; 23 }e[maxn<<2]; 24 void add(int u, int v) 25 { 26 e[++cnt].v = v; 27 e[cnt].next = head[u]; 28 head[u] = cnt; 29 } 30 bool dfs(int u) 31 { 32 int v = head[u]; 33 for(int i = v; i != 0; i = e[i].next) 34 { 35 if(!vis[e[i].v]) 36 { 37 vis[e[i].v] = 1; 38 if(!link[e[i].v] || dfs(link[e[i].v])) 39 { 40 link[e[i].v] = u; 41 return 1; 42 } 43 } 44 } 45 return 0; 46 } 47 int main() 48 { 49 int u,v; 50 n = read(); 51 for(int i = 1; i <= n*2; i++) 52 { 53 u = read(); v = read(); 54 add(i,u); 55 add(i,u+n); 56 add(i,v); 57 add(i,v+n); 58 } 59 for(int i = 1; i <= n*2; i++) 60 { 61 memset(vis,0,sizeof(vis)); 62 if(dfs(i)) ans++; 63 } 64 printf("%d",ans); 65 return 0; 66 }
