给n个灯和m个开关， 每个灯可以由若干个开关控制， 每个开关也可以控制若干个灯， 问你能否找到一种开关的状态， 使得所有的灯都亮。
将灯作为列， 然后把每个开关拆成两行， 开是一行， 关是一行。 然后跑一下就可以。 输出路径的话， 就是用一个vis数组记录一下哪些行被访问过。
#include<bits/stdc++.h>
using namespace std;
#define pb(x) push_back(x)
#define ll long long
#define mk(x, y) make_pair(x, y)
#define lson l, m, rt<<1
#define mem(a) memset(a, 0, sizeof(a))
#define rson m+1, r, rt<<1|1
#define mem1(a) memset(a, -1, sizeof(a))
#define mem2(a) memset(a, 0x3f, sizeof(a))
#define rep(i, a, n) for(int i = a; i<n; i++)
#define ull unsigned long long
typedef pair<int, int> pll;
const double PI = acos(-1.0);
const double eps = 1e-;
const int mod = 1e9+;
const int inf = ;
const int dir[][] = { {-, }, {, }, {, -}, {, } };
const int maxn = ;
const int maxNode = ;
int num;
struct DLX {
int L[maxNode], R[maxNode], U[maxNode], D[maxNode], row[maxNode], col[maxNode];
int S[maxn], H[maxn], sz, n, m, vis[maxn*];
void remove(int c) {
for(int i = D[c]; i!=c; i = D[i]) {
L[R[i]] = L[i];
R[L[i]] = R[i];
}
}
void resume(int c) {
for(int i = U[c]; i!=c; i = U[i]) {
L[R[i]] = i;
R[L[i]] = i;
}
}
int dfs(int d) {
if(R[] == ) {
return ;
}
int c = R[];
for(int i = R[]; i!=; i = R[i])
if(S[c]>S[i])
c = i;
for(int i = D[c]; i!=c; i = D[i]) {
if(vis[row[i]^])
continue;
remove(i);
vis[row[i]] = ;
for(int j = R[i]; j != i; j = R[j])
remove(j);
if(dfs(d+))
return ;
for(int j = L[i]; j != i; j = L[j])
resume(j);
resume(i);
vis[row[i]] = ;
}
return ;
}
void add(int r, int c) {
sz++;
row[sz] = r;
col[sz] = c;
S[c]++;
U[sz] = U[c];
D[sz] = c;
D[U[c]] = sz;
U[c] = sz;
if(~H[r]) {
R[sz] = H[r];
L[sz] = L[H[r]];
L[R[sz]] = sz;
R[L[sz]] = sz;
} else {
H[r] = L[sz] = R[sz] = sz;
}
}
void init() {
mem1(H);
for(int i = ; i<=n; i++) {
R[i] = i+;
L[i] = i-;
U[i] = i;
D[i] = i;
}
mem(S);
R[n] = ;
L[] = n;
sz = n;
}
void solve() {
init();
mem(vis);
int x, y;
char s[];
for(int i = ; i <= n; i++) {
scanf("%d", &x);
while(x--) {
scanf("%d%s", &y, s);
if(s[] == 'N') {
add(y<<, i);
} else {
add(y<<|, i);
}
}
}
if(dfs()) {
for(int i = ; i <= m-; i ++) {
if(vis[i<<]) {
printf("ON ");
} else {
printf("OFF ");
}
}
if(vis[*m]) {
puts("ON");
} else {
puts("OFF");
}
} else {
puts("-1");
}
}
}dlx;
int main()
{
while(~scanf("%d%d", &dlx.n, &dlx.m)) {
dlx.solve();
}
return ;
}