POJ 2446 binary maximum match

Q: I will give you an N * M graph, and then cover it with 1*2 cards. Some points cannot be covered. Check whether it can completely overwrite binary matching to find out whether the maximum match is equal to the number of points that can be covered. [Cpp] # include # Include # Include# Include # Include # Include # Include # Include # Include # Include # Include # Include # Define PI acos (-1.0) # define Max 2005 # define inf 1 <28 # define LL (x) (x <1) # define RR (x) (x <1 | 1) # define Rep (I, s, t) for (int I = (s); I <= (t); ++ I) # define ll long # define mem (a, B) memset (a, B, sizeof (a) # define mp (a, B) make_pair (a, B) using namespace std; struct kdq {int e, next;} ed [Max * 10]; int head [Max], num; void add (int s, int e) {ed [num]. e = e; ed [num]. next = head [s]; head [s] = Num ++;} int link [Max]; bool vis [Max]; int dfs (int x) {for (int I = head [x]; I! =-1; I = ed [I]. next) {int e = ed [I]. e; if (! Vis [e]) {vis [e] = 1; if (link [e] =-1 | dfs (link [e]) {link [e] = x; return 1 ;}} return 0 ;}int Map [50] [50]; int n, m, k; int mx [4] = {0, 0, 1,-1}; int my [4] = {1,-1, 0, 0}; int inmap (int x, int y) {if (x> = 1 & x <= n & y> = 1 & y <= m &&! Map [x] [y]) return 1; return 0;} int Mapnum [50] [50]; int nn = 0; void init () {mem (vis, 0); mem (head,-1); mem (link,-1); mem (Map, 0); mem (Mapnum, 0); nn = 0 ;} void build () {for (int I = 1; I <= n; I ++) {for (int j = 1; j <= m; j ++) {if (Map [I] [j] = 0) Mapnum [I] [j] = ++ nn ;}} for (int I = 1; I <= n; I ++) {for (int j = 1; j <= m; j ++) {if (! Map [I] [j]) {for (int k = 0; k <4; k ++) {int tx = I + mx [k]; int ty = j + my [k]; if (inmap (tx, ty) {add (Mapnum [I] [j], mapnum [tx] [ty]) ;}}}} int main () {while (cin >>n> m >>> k) {init (); int d = k; while (d --) {int a, B; scanf ("% d", & a, & B ); map [B] [a] = 1;} build (); int ans = 0; for (int I = 1; I <= nn; I ++) {mem (vis, 0); ans + = dfs (I);} int cnt = n * m-k; if ((Cnt & 1) | (ans! = Cnt) cout <"NO" < Else cout <"YES" < } Return 0;