bzoj 1191: [HNOI2006]超级英雄Hero
一开始还以为用2-SAT。。
愣了几分钟才发现是二分图匹配，
用匈牙利算法找匹配碰到一个不能匹配的就退出就可以了。
1 /* 2 ID:WULALA 3 PROB:bzoj1191 4 LANG:C++ 5 */ 6 #include <cstdio> 7 #include <cstring> 8 #include <algorithm> 9 #include <cmath> 10 #include <iostream> 11 #include <ctime> 12 #include <set> 13 #define N 1008 14 #define M 1008 15 #define mod 16 #define mid(l,r) ((l+r) >> 1) 17 #define INF 0x7ffffff 18 using namespace std; 19 20 int n,m,tot,Link[M],ans,head[N],vis[M]; 21 22 struct WULALA 23 { 24 int node,next; 25 }e[2 * N]; 26 27 bool find(int a) 28 { 29 int c = head[a]; 30 for (;c;c =e[c].next) 31 if (!vis[e[c].node]) 32 { 33 vis[e[c].node] = true; 34 if (Link[e[c].node] == -1 || find(Link[e[c].node])) 35 { 36 Link[e[c].node] = a; 37 return true; 38 } 39 } 40 return false; 41 } 42 43 int main() 44 { 45 scanf("%d%d",&m,&n); 46 memset(Link,255,sizeof(Link)); 47 for (int i = 1;i <= n;i++) 48 { 49 int a,b; 50 scanf("%d%d",&a,&b); 51 e[++tot].node = a; 52 e[tot].next = head[i]; 53 head[i] = tot; 54 e[++tot].node = b; 55 e[tot].next = head[i]; 56 head[i] = tot; 57 } 58 for (int i = 1;i <= n;i++) 59 { 60 memset(vis,0,sizeof(vis)); 61 if (find(i)) ans++; 62 else break; 63 } 64 printf("%d\n",ans); 65 return 0; 66 }
