<div class="post_brief"><p>
有离线镜像还是能省不少流量。开心。不过流量还是用得飞快啊。</p>
这就是个cdq重构的题。学习了前几天xyz大爷讲的扔线段树的做法,省了不少代码。
#include <cstdio> #include <cstring> #include <algorithm>using namespace std;
struct node { int v, c; node *next; }; struct seg { int l, r; node *head; seg *ls, *rs; };
const int maxa = 209; const int maxn = 40009; const int maxm = 10009; const int maxnd = maxn * 23; const int mov[4][2] = {{1, 0}, {-1, 0}, {0, 1}, {0, -1}};
#define upmax(a,b) {
if (a < b)
a = b;
} #define mkpos(x,y) (((x)<<16)|(y)) #define getx(a) ((a)>>16) #define gety(a) ((a)&0x0000ffff) #define nid(x,y) (((x)*n)+(y))struct disjoint_set { int r[maxn], h[maxn]; int vst[maxn], rst[maxn], ust[maxn], hst[maxn], tst; inline disjoint_set() { tst = 0; } void init(int n) { for (int i = 0; i < n; ++ i) r[i] = i, h[i] = 1; } int getRoot(int x) { for (; r[x] ^ x; x = r[x]); return x; } inline void merge(int u, int v) { u = getRoot(u), v = getRoot(v); if (h[u] < h[v]) swap(u, v); vst[++ tst] = v; rst[tst] = r[v]; r[v] = u; ust[tst] = u; hst[tst] = h[u]; upmax(h[u], h[v] + 1); } void recover(int x) { while (tst > x) { r[vst[tst]] = rst[tst]; h[vst[tst]] = hst[tst]; – tst; } } };
node nlst[maxnd], *np(nlst); seg slst[maxn * 3], *sp(slst), *rt; int n, m, a[maxa][maxa], cc[maxa][maxa], pret[maxa][maxa], ansb[maxm], answ[maxm];
#define midp(p) ((p->l+p->r)>>1)
inline seg* sgtBuild(int l, int r) { seg* p(sp ++); p-> l = l; p-> r = r; p-> head = 0; if (l + 1 < r) { p-> ls = sgtBuild(l, midp(p)); p-> rs = sgtBuild(midp(p), r); } return p; } inline void sgtIns(seg* p, int l, int r, int ps, int cl) { if (p-> l == l && p-> r == r) { np-> v = ps; np-> c = cl; np-> next = p-> head; p-> head = np ++; } else if (r <= midp(p)) sgtIns(p-> ls, l, r, ps, cl); else if (l >= midp(p)) sgtIns(p-> rs, l, r, ps, cl); else { sgtIns(p-> ls, l, midp(p), ps, cl); sgtIns(p-> rs, midp(p), r, ps, cl); } }
disjoint_set r;
void sgtDfs(seg* p, int cb, int cw) { int rp(r. tst); for (node* it = p-> head; it; it = it-> next) { int x(getx(it-> v)), y(gety(it-> v)), c(it-> c), *v; if (c == 0) v = &cw; else v = &cb; ++ *v; cc[x][y] = c; for (int mi = 0; mi < 4; ++ mi) { int x1(x + mov[mi][0]), y1(y + mov[mi][1]); if (x1 < 0 || x1 >= n || y1 < 0 || y1 >= n) continue; if (cc[x1][y1] == c && r. getRoot(nid(x, y)) != r. getRoot(nid(x1, y1))) { – v; r. merge(nid(x, y), nid(x1, y1)); } } } if (p-> l + 1 == p-> r) { ansb[p-> l] = cb; answ[p-> l] = cw; } else { sgtDfs(p-> ls, cb, cw); sgtDfs(p-> rs, cb, cw); } for (node it = p-> head; it; it = it-> next) { int x(getx(it-> v)), y(gety(it-> v)); cc[x][y] = -1; } r. recover(rp); }
int main() { #ifndef ONLINE_JUDGE freopen(“in.txt”, “r”, stdin); #endif
scanf("%d", &n); for (int i = 0; i < n; ++ i) for (int j = 0; j < n; ++ j) { scanf("%d", a[i] + j); pret[i][j] = 0; } scanf("%d", &m); rt = sgtBuild(0, m + 1); for (int i = 1; i <= m; ++ i) { int x, y; scanf("%d%d", &x, &y); -- x; -- y; sgtIns(rt, pret[x][y], i, mkpos(x, y), a[x][y]); a[x][y] ^= 1; pret[x][y] = i; } for (int i = 0; i < n; ++ i) for (int j = 0; j < n; ++ j) sgtIns(rt, pret[i][j], m + 1, mkpos(i, j), a[i][j]); memset(cc, 0, sizeof(cc)); r. init(n * n); memset(cc, -1, sizeof(cc)); sgtDfs(rt, 0, 0); for (int i = 1; i <= m; ++ i) printf("%d %d\n", ansb[i], answ[i]);
}