http://codeforces.com/contest/489/problem/B
二分匹配模板题
1 public class Main {
2 static final int maxn = 2000;
3 static int n, m;
4 static int[] a = new int[maxn];
5 static int[] b = new int[maxn];
6 static int[] c = new int[maxn];
7 static int[] vis = new int[maxn];
8
9 public static void main(String[] args) {
10 Scanner io = new Scanner(System.in);
11 n = io.nextInt();
12 for (int i = 0; i < n; i++) a[i] = io.nextInt();
13
14 m = io.nextInt();
15 Arrays.fill(c, -1);
16 int ans = 0;
17 for (int i = 0; i < m; i++) b[i] = io.nextInt();
18 for (int i = 0; i < n; i++) {
19 Arrays.fill(vis, 0);
20 match(i);
21 }
22 for (int i = 0; i < m; i++) if (c[i] != -1) ans++;
23 System.out.println(ans);
24 }
25
26 static boolean match(int i) {
27 //递归不走回头路，针对的是自己这一列，所以放在最前面
28 if (vis[i] == 1) return false;
29 vis[i] = 1;
30 for (int j = 0; j < m; j++) {
31 if (Math.abs(b[j] - a[i]) <= 1 && (c[j] == -1 || match(c[j]))) {
32 c[j] = i;
33 return true;
34 }
35 }
36 return false;
37 }
38 }