[CQOI2009]dance跳舞

每个人拆成两个点，一个表示接受喜欢的，一个表示不接受喜欢的，（男yes，男no，女yes，女no）
男yes->男no，容量为k；女no->女yes，容量为k
男女喜欢，则男yes->女yes，容量为1
否则男no->女no，容量为1

二分歌曲x，S->男yes，容量为x；女yes->T，容量为x
若最大流==n*x则满足要求

# include <bits/stdc++.h>
# define IL inline
# define RG register
# define Fill(a, b) memset(a, b, sizeof(a))
# define Copy(a, b) memcpy(a, b, sizeof(a))
using namespace std;
typedef long long ll;
const int _(210), __(4e4 + 10), INF(2147483647);

IL ll Read(){
    RG char c = getchar(); RG ll x = 0, z = 1;
    for(; c < '0' || c > '9'; c = getchar()) z = c == '-' ? -1 : 1;
    for(; c >= '0' && c <= '9'; c = getchar()) x = (x << 1) + (x << 3) + (c ^ 48);
    return x * z;
}

int n, k, w[__], fst[_], nxt[__], to[__], cnt, tmp1[_], tcnt, tmp2[__];
int S, T, lev[_], cur[_], max_flow, ans;
queue <int> Q;

IL void Add(RG int u, RG int v, RG int f){
    w[cnt] = f; to[cnt] = v; nxt[cnt] = fst[u]; fst[u] = cnt++;
    w[cnt] = 0; to[cnt] = u; nxt[cnt] = fst[v]; fst[v] = cnt++;
}

IL int Dfs(RG int u, RG int maxf){
    if(u == T) return maxf;
    RG int ret = 0;
    for(RG int &e = cur[u]; e != -1; e = nxt[e]){
        if(lev[to[e]] != lev[u] + 1 || !w[e]) continue;
        RG int f = Dfs(to[e], min(w[e], maxf - ret));
        ret += f; w[e ^ 1] += f; w[e] -= f;
        if(ret == maxf) break;
    }
    return ret;
}

IL bool Bfs(){
    Fill(lev, 0); lev[S] = 1; Q.push(S);
    while(!Q.empty()){
        RG int u = Q.front(); Q.pop();
        for(RG int e = fst[u]; e != -1; e = nxt[e]){
            if(lev[to[e]] || !w[e]) continue;
            lev[to[e]] = lev[u] + 1;
            Q.push(to[e]);
        }
    }
    return lev[T];
}

IL bool Check(RG int x){
    Copy(fst, tmp1); cnt = tcnt; Copy(w, tmp2);
    for(RG int i = 1; i <= n; i++) Add(S, i, x), Add(i + 3 * n, T, x);
    max_flow = 0;
    while(Bfs()) Copy(cur, fst), max_flow += Dfs(S, INF);
    return max_flow == x * n;
}

int main(RG int argc, RG char* argv[]){
    n = Read(); k = Read(); Fill(fst, -1); T = 4 * n + 1;
    for(RG int i = 1; i <= n; i++) Add(i, i + n, k), Add(i + 2 * n, i + 3 * n, k);
    for(RG int i = 1; i <= n; i++)
        for(RG int j = 1; j <= n; j++){
            RG char c; scanf(" %c", &c);
            if(c == 'Y') Add(i, j + 3 * n, 1);
            else Add(i + n, j + 2 * n, 1);
        }
    Copy(tmp1, fst); Copy(tmp2, w); tcnt = cnt;
    RG int l = 0, r = n;
    while(l <= r){
        RG int mid = (l + r) >> 1;
        if(Check(mid)) ans = mid, l = mid + 1;
        else r = mid - 1;
    }
    printf("%d\n", ans);
    return 0;
}