bzoj 2243 2243: [SDOI2011]染色 树链剖分

直接树链剖分就可以啦。

  1 #include <cstdio>
  2 #include <cstring>
  3 #include <cmath>
  4 #include <algorithm>
  5 using namespace std;
  6 const int MAXN = 110000;
  7 typedef int ll;
  8 int head[MAXN],to[MAXN * 2],nxt[MAXN * 2],q[MAXN],dep[MAXN],son[MAXN],siz[MAXN],top[MAXN],pos[MAXN],idx[MAXN],fa[MAXN],jl[MAXN];
  9 int data[MAXN * 5],lcol[MAXN * 5],rcol[MAXN * 5],lzy[MAXN * 5],p[MAXN][32];
 10 int n,m,a,b,c,sum,cnt;
 11 int col[MAXN];
 12 char s[10];
 13 void add(int a,int b)
 14 {
 15     nxt[++cnt] = head[a];
 16     to[cnt] = b;
 17     head[a] = cnt;
 18 }
 19 void updata(int k)
 20 {
 21     if (rcol[k << 1] == lcol[k << 1 | 1]) 
 22         data[k] = data[k << 1] + data[k << 1 | 1] - 1;
 23     else 
 24         data[k] = data[k << 1] + data[k << 1 | 1];
 25     lcol[k] = lcol[k << 1];
 26     rcol[k] = rcol[k << 1 | 1];
 27 }
 28 void build(int k,int l,int r)
 29 {
 30     lzy[k] = -1;
 31     if (l == r) 
 32     {
 33         data[k] = 1;
 34         lcol[k] = rcol[k] = col[idx[l]];
 35         return;
 36     }
 37     int midn = l + r >> 1;
 38     build(k << 1,l,midn);
 39     build(k << 1 | 1,midn + 1,r);
 40     updata(k);
 41 }
 42 void lca_init()
 43 {
 44     for (int j = 1;(1 << j) <= n;j++)
 45         for (int i = 1;i <= n;i++)
 46             p[i][j] = p[p[i][j - 1]][j - 1];
 47 }
 48 void init()
 49 {
 50     int que = 0,u,v;
 51     q[++que] = 1;
 52     dep[1] = 1;
 53     for (int i = q[que];i <= que;i++)
 54     {
 55         siz[u = q[i]] = 1;
 56         for (int o = head[u];o;o = nxt[o])
 57         {
 58             v = to[o];
 59             if (v == fa[u]) 
 60                 continue;
 61             fa[v] = u;
 62             p[v][0] = u;
 63             dep[v] = dep[u] + 1;
 64             q[++que] = v;
 65         }
 66     }
 67     for (int i = que;i >= 1;i--)
 68     {
 69         u = q[i];
 70         siz[v = fa[u]] += siz[u];
 71         if (siz[u] > siz[son[v]]) 
 72             son[v] = u;
 73     }
 74     for (int i = 1;i <= que;i++)
 75     {
 76         if (top[u = q[i]]) 
 77             continue;
 78         for (v = u;v;v = son[v])
 79         {
 80             top[v] = u;
 81             idx[pos[v] = ++sum] = v;
 82         }
 83     }
 84     build(1,1,sum);
 85     lca_init();
 86 }
 87 int lca(int a,int b)
 88 {
 89     if (dep[a] < dep[b]) swap(a,b);
 90     for (int j = log2(n);j >= 0;j--)
 91         if (dep[a] - (1 << j) >= dep[b])
 92             a = p[a][j];
 93     if (a == b) return b;
 94     for (int j = log2(n);j >= 0;j--)
 95         if (p[a][j] != p[b][j])
 96         {
 97             a = p[a][j];
 98             b = p[b][j];
 99         }
100     return p[a][0];
101 }
102 void push_down(int k)
103 {
104     data[k << 1] = data[k << 1 | 1] = 1;
105     lzy[k << 1] = lzy[k << 1 | 1] = lzy[k];
106     lcol[k << 1] = rcol[k << 1] = lcol[k << 1 | 1] = rcol[k << 1 | 1] = lzy[k];
107     lzy[k] = -1;
108 }
109 void vec_chg(int k,int l,int r,int x,int y,int xg)
110 {
111     if (x <= l && r <= y)
112     {
113         lzy[k] = xg;
114         lcol[k] = rcol[k] = xg;
115         data[k] = 1;
116         return;
117     }
118     if (lzy[k] >= 0) push_down(k);
119     int midn = l + r >> 1;
120     if (x <= midn) vec_chg(k << 1,l,midn,x,y,xg);
121     if (y > midn) vec_chg(k << 1 | 1,midn + 1,r,x,y,xg);
122     updata(k);
123 }
124 int vec_qry(int k,int l,int r,int x,int y)
125 {
126     if (x <= l && r <= y) return data[k];
127     if (lzy[k] >= 0) push_down(k);
128     int midn = l + r >> 1,res = 0;
129     if (x <= midn) res += vec_qry(k << 1,l,midn,x,y);
130     if (y > midn) res += vec_qry(k << 1 | 1,midn + 1,r,x,y);
131     if (x <= midn && y > midn) if (rcol[k << 1] == lcol[k << 1 | 1]) res--;
132     return res;
133 }
134 int vec_col(int k,int l,int r,int x,int y)
135 {
136     if (x <= l && r <= y) return lcol[k];
137     if (lzy[k] >= 0) push_down(k);
138     int midn = l + r >> 1;
139     if (x <= midn) return vec_col(k << 1,l,midn,x,y);
140     if (y > midn) return vec_col(k << 1 | 1,midn + 1,r,x,y);
141 }
142 void query_chg(int a,int b,int xg)
143 {
144     while (top[a] != top[b])
145     {
146         if (dep[top[a]] < dep[top[b]]) swap(a,b);
147         vec_chg(1,1,sum,pos[top[a]],pos[a],xg);
148         a = fa[top[a]];
149     }
150     if (dep[a] > dep[b]) swap(a,b);
151     vec_chg(1,1,sum,pos[a],pos[b],xg);
152 }
153 int query_sum(int a,int b)
154 {
155     int res = 0;
156     while (top[a] != top[b])
157     {
158         if (dep[top[a]] < dep[top[b]]) swap(a,b);
159         res += vec_qry(1,1,sum,pos[top[a]],pos[a]);
160         if (vec_col(1,1,sum,pos[top[a]],pos[top[a]]) == vec_col(1,1,sum,pos[fa[top[a]]],pos[fa[top[a]]])) res--;
161         a = fa[top[a]];
162     }
163     if (dep[a] > dep[b]) swap(a,b);
164     res += vec_qry(1,1,sum,pos[a],pos[b]);
165     return res;
166 }
167 int main()
168 {
169     scanf("%d%d",&n,&m);
170     for (int i = 1;i <= n;i++) 
171         scanf("%d",&col[i]);
172     for (int i = 1;i <= n - 1;i++) 
173     {   
174         scanf("%d%d",&a,&b);
175         add(a,b);
176         add(b,a);
177     }
178     init();
179     for (int i = 1;i <= m;i++)
180     {
181         scanf("%s",s);
182         if (s[0] == 'C')
183         {
184             scanf("%d%d%d",&a,&b,&c);
185             query_chg(a,b,c);
186         }else
187         {
188             scanf("%d%d",&a,&b);
189             int tt = lca(a,b);
190             printf("%d\n",query_sum(a,tt) + query_sum(b,tt) - 1);
191         }
192     }
193     return 0;
194 }