#include <cstdio> #include <cstring> #include <vector> #include <queue> #include <stack> #include <cmath> using namespace std; const int maxn = 3010; const int INF = 1<<28; int dx[maxn], dy[maxn]; int cx[maxn], cy[maxn]; vector <int> G[maxn]; int dis; int n, m; bool vis[maxn]; bool search() { queue <int> Q; int dis = INF; memset(dx, -1, sizeof(dx)); memset(dy, -1, sizeof(dy)); for(int i = 0; i < n; i++) if(cx[i] == -1) { Q.push(i); dx[i] = 0; } while(!Q.empty()) { int u = Q.front(); Q.pop(); if(dx[u] > dis) break; for(int i = 0; i < G[u].size(); i++) { int v = G[u][i]; if(dy[v] == -1) { dy[v] = dx[u] + 1; if(cy[v] == -1) dis = dy[v]; else { dx[cy[v]] = dy[v] + 1; Q.push(cy[v]); } } } } return dis != INF; } bool dfs(int u) { for(int i = 0; i < G[u].size(); i++) { int v = G[u][i]; if(vis[v]) continue; vis[v] = true; if(dy[v] == dx[u]+1) { if(cy[v] != -1 && dy[v] == dis) continue; if(cy[v] == -1 || dfs(cy[v])) { cy[v] = u; cx[u] = v; return true; } } } return false; } int match() { int ans = 0; memset(cx, -1, sizeof(cx)); memset(cy, -1, sizeof(cy)); while(search()) { memset(vis, 0, sizeof(vis)); for(int i = 0; i < n; i++) if(cx[i] == -1 && dfs(i)) ans++; } return ans; }
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原文地址:http://blog.csdn.net/u011686226/article/details/37050067