[luoguP2486] [SDOI2011]染色(树链剖分)
就是个模板啦
记录每一个点的左端点颜色和右端点颜色和当前端点颜色段数。
合并时如果左孩子右端点和右孩子左端点不同就 ans--
在重链上跳的时候别忘记统计一下
——代码
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 | #include <cstdio> #include <cstring> #include <iostream> #define N 400001 #define ls now << 1 #define rs now << 1 | 1 #define swap(x, y) ((x) ^= (y) ^= (x) ^= (y)) #define pushup(now) Lcol[now] = Lcol[ls], Rcol[now] = Rcol[rs], col[now] = col[ls] + col[rs] - (Rcol[ls] == Lcol[rs]) int n, m, cnt, tim; int head[N], to[N << 1], next[N << 1]; int a[N], f[N], deep[N], size[N], son[N], tid[N], top[N], rank[N], L[N], R[N], Lcol[N], Rcol[N], col[N], laz[N]; inline int read() { int x = 0, f = 1; char ch = getchar (); for (; ! isdigit (ch); ch = getchar ()) if (ch == '-' ) f = -1; for (; isdigit (ch); ch = getchar ()) x = (x << 1) + (x << 3) + ch - '0' ; return x * f; } inline void add( int x, int y) { to[cnt] = y; next[cnt] = head[x]; head[x] = cnt++; } inline void dfs1( int u) { int i, v; size[u] = 1; deep[u] = deep[f[u]] + 1; for (i = head[u]; i ^ -1; i = next[i]) { v = to[i]; if (v ^ f[u]) { f[v] = u; dfs1(v); size[u] += size[v]; if (son[u] == -1 || size[son[u]] < size[v]) son[u] = v; } } } inline void dfs2( int u, int t) { int i, v; top[u] = t; tid[u] = ++tim; rank[tim] = u; if (son[u] == -1) return ; dfs2(son[u], t); for (i = head[u]; i ^ -1; i = next[i]) { v = to[i]; if (v ^ f[u] && v ^ son[u]) dfs2(v, v); } } inline void build( int now, int l, int r) { L[now] = l; R[now] = r; if (l == r) { col[now] = 1; Lcol[now] = Rcol[now] = a[rank[l]]; return ; } int mid = (l + r) >> 1; build(ls, l, mid); build(rs, mid + 1, r); pushup(now); } inline void pushdown( int now) { if (laz[now]) { col[ls] = col[rs] = 1; laz[ls] = laz[rs] = Lcol[ls] = Lcol[rs] = Rcol[ls] = Rcol[rs] = laz[now]; laz[now] = 0; } } inline void update( int now, int l, int r, int z) { if (l <= L[now] && R[now] <= r) { col[now] = 1; laz[now] = Lcol[now] = Rcol[now] = z; return ; } pushdown(now); int mid = (L[now] + R[now]) >> 1; if (l <= mid) update(ls, l, r, z); if (mid < r) update(rs, l, r, z); pushup(now); } inline void q_update( int u, int v, int z) { while (top[u] ^ top[v]) { if (deep[top[u]] < deep[top[v]]) swap(u, v); update(1, tid[top[u]], tid[u], z); u = f[top[u]]; } if (deep[u] > deep[v]) swap(u, v); update(1, tid[u], tid[v], z); } inline int q_color( int now, int x) { if (L[now] == R[now]) return Lcol[now]; pushdown(now); int mid = (L[now] + R[now]) >> 1; if (x <= mid) return q_color(ls, x); else return q_color(rs, x); } inline int query( int now, int l, int r) { if (l <= L[now] && R[now] <= r) return col[now]; pushdown(now); int mid = (L[now] + R[now]) >> 1, ans = 0; if (l <= mid) ans += query(ls, l, r); if (mid < r) ans += query(rs, l, r); if (l <= mid && mid < r) ans -= (Rcol[ls] == Lcol[rs]); return ans; } inline int q_query( int u, int v) { int ans = 0; while (top[u] ^ top[v]) { if (deep[top[u]] < deep[top[v]]) swap(u, v); ans += query(1, tid[top[u]], tid[u]); ans -= (q_color(1, tid[f[top[u]]]) == q_color(1, tid[top[u]])); u = f[top[u]]; } if (deep[u] > deep[v]) swap(u, v); ans += query(1, tid[u], tid[v]); return ans; } int main() { int i, x, y, z; char s[10]; n = read(); m = read(); memset (son, -1, sizeof (son)); memset (head, -1, sizeof (head)); for (i = 1; i <= n; i++) a[i] = read(); for (i = 1; i < n; i++) { x = read(); y = read(); add(x, y); add(y, x); } dfs1(1); dfs2(1, 1); build(1, 1, n); for (i = 1; i <= m; i++) { scanf ( "%s" , s); x = read(); y = read(); if (s[0] == 'C' ) { z = read(); q_update(x, y, z); } else printf ( "%d\n" , q_query(x, y)); } return 0; } |
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