树链剖分的入门题目，自己写了下感觉还是挺好写的，不过真的有点长...
spoj 375 边有权值：
1 #include <iostream>
2 #include <cstring>
3 #include <cstdio>
4 using namespace std;
5
6 const int INF = -999999999;
7 const int N = 10001;
8 int head[N];
9 int sz[N];
10 int depth[N];
11 int num[N];
12 int top[N];
13 int dfn[N];
14 int hc[N];
15 int fa[N];
16 int n, e, dfs_clock;
17
18 void init()
19 {
20 e = dfs_clock = 0;
21 memset( head, -1, sizeof(head) );
22 }
23
24 struct Edge
25 {
26 int v, w, next;
27 } edge[N << 1];
28
29 void addEdge( int u, int v, int w )
30 {
31 edge[e].v = v;
32 edge[e].w = w;
33 edge[e].next = head[u];
34 head[u] = e++;
35 }
36
37 void dfs1( int u, int pre, int dep )
38 {
39 sz[u] = 1;
40 fa[u] = pre;
41 depth[u] = dep;
42 hc[u] = -1;
43 for ( int i = head[u]; i != -1; i = edge[i].next )
44 {
45 int v = edge[i].v;
46 if ( v == pre ) continue;
47 dfs1( v, u, dep + 1 );
48 sz[u] += sz[v];
49 if ( hc[u] == -1 || sz[v] > sz[hc[u]] )
50 {
51 hc[u] = v;
52 }
53 }
54 }
55
56 void dfs2( int u, int tp )
57 {
58 top[u] = tp;
59 dfn[u] = ++dfs_clock;
60 if ( hc[u] != -1 )
61 {
62 dfs2( hc[u], tp );
63 }
64 for ( int i = head[u]; i != -1; i = edge[i].next )
65 {
66 int v = edge[i].v;
67 if ( v == fa[u] ) continue;
68 if ( v == hc[u] )
69 {
70 num[dfn[v]] = edge[i].w;
71 }
72 else
73 {
74 dfs2( v, v );
75 num[dfn[v]] = edge[i].w;
76 }
77 }
78 }
79
80 struct Node
81 {
82 int l, r, maxn;
83 } node[N << 2];
84
85 void pushup( int i )
86 {
87 node[i].maxn = max( node[i << 1].maxn, node[i << 1 | 1].maxn );
88 }
89
90 void build( int i, int l, int r )
91 {
92 node[i].l = l, node[i].r = r;
93 if ( l == r )
94 {
95 node[i].maxn = num[l];
96 return ;
97 }
98 int mid = ( l + r ) >> 1;
99 build( i << 1, l, mid );
100 build( i << 1 | 1, mid + 1, r );
101 pushup(i);
102 }
103
104 void update( int i, int pos, int val )
105 {
106 if ( node[i].l == pos && node[i].r == pos )
107 {
108 node[i].maxn = val;
109 return ;
110 }
111 int mid = ( node[i].l + node[i].r ) >> 1;
112 if ( pos <= mid )
113 {
114 update( i << 1, pos, val );
115 }
116 else
117 {
118 update( i << 1 | 1, pos, val );
119 }
120 pushup(i);
121 }
122
123 int query( int i, int l, int r )
124 {
125 if ( node[i].l == l && node[i].r == r )
126 {
127 return node[i].maxn;
128 }
129 int mid = ( node[i].l + node[i].r ) >> 1;
130 if ( r <= mid )
131 {
132 return query( i << 1, l, r );
133 }
134 else if ( l > mid )
135 {
136 return query( i << 1 | 1, l, r );
137 }
138 else
139 {
140 return max( query( i << 1, l, mid ), query( i << 1 | 1, mid + 1, r ) );
141 }
142 }
143
144 struct Data
145 {
146 int u, v;
147 } d[N];
148
149 int tree_query( int x, int y )
150 {
151 int ans = INF;
152 while ( top[x] != top[y] )
153 {
154 if ( depth[top[x]] < depth[top[y]] )
155 {
156 swap( x, y );
157 }
158 ans = max( ans, query( 1, dfn[top[x]], dfn[x] ) );
159 x = fa[top[x]];
160 }
161 if ( x != y )
162 {
163 if ( depth[x] > depth[y] ) swap( x, y );
164 ans = max( ans, query( 1, dfn[x] + 1, dfn[y] ) );
165 }
166 return ans;
167 }
168
169 void tree_update( int x, int y )
170 {
171 int u = d[x].u, v = d[x].v;
172 if ( depth[u] < depth[v] ) u = v;
173 update( 1, dfn[u], y );
174 }
175
176 int main ()
177 {
178 int t;
179 scanf("%d", &t);
180 while ( t-- )
181 {
182 scanf("%d", &n);
183 init();
184 for ( int i = 1; i < n; i++ )
185 {
186 int u, v, w;
187 scanf("%d%d%d", &u, &v, &w);
188 addEdge( u, v, w );
189 addEdge( v, u, w );
190 d[i].u = u, d[i].v = v;
191 }
192 dfs1( 1, -1, 1 );
193 dfs2( 1, 1 );
194 build( 1, 2, n );
195 char op[11];
196 int x, y;
197 while ( 1 )
198 {
199 scanf("%s", op);
200 if ( op[0] == ‘D‘ ) break;
201 scanf("%d%d", &x, &y);
202 if ( op[0] == ‘Q‘ )
203 {
204 printf("%d\n", tree_query( x, y ));
205 }
206 else
207 {
208 tree_update( x, y );
209 }
210 }
211 }
212 return 0;
213 }
bzoj 1036 点有权值：
1 #include <iostream>
2 #include <cstring>
3 #include <cstdio>
4 using namespace std;
5
6 const int INF = -9999999;
7 const int N = 30001;
8 int c[N];
9 int head[N];
10 int sz[N];
11 int depth[N];
12 int num[N];
13 int top[N];
14 int dfn[N];
15 int hc[N];
16 int fa[N];
17 int n, e, dfs_clock;
18
19 void init()
20 {
21 e = dfs_clock = 0;
22 memset( head, -1, sizeof(head) );
23 }
24
25 struct Edge
26 {
27 int v, next;
28 } edge[N << 1];
29
30 void addEdge( int u, int v )
31 {
32 edge[e].v = v;
33 edge[e].next = head[u];
34 head[u] = e++;
35 }
36
37 void dfs1( int u, int pre, int dep )
38 {
39 sz[u] = 1;
40 fa[u] = pre;
41 depth[u] = dep;
42 hc[u] = -1;
43 for ( int i = head[u]; i != -1; i = edge[i].next )
44 {
45 int v = edge[i].v;
46 if ( v == pre ) continue;
47 dfs1( v, u, dep + 1 );
48 sz[u] += sz[v];
49 if ( hc[u] == -1 || sz[v] > sz[hc[u]] )
50 {
51 hc[u] = v;
52 }
53 }
54 }
55
56 void dfs2( int u, int tp )
57 {
58 top[u] = tp;
59 dfn[u] = ++dfs_clock;
60 num[dfn[u]] = c[u];
61 if ( hc[u] != -1 )
62 {
63 dfs2( hc[u], tp );
64 }
65 for ( int i = head[u]; i != -1; i = edge[i].next )
66 {
67 int v = edge[i].v;
68 if ( v == fa[u] || v == hc[u] ) continue;
69 dfs2( v, v );
70 }
71 }
72
73 struct Node
74 {
75 int l, r;
76 int maxn, sum;
77 } node[N << 2];
78
79 void pushup( int i )
80 {
81 node[i].maxn = max( node[i << 1].maxn, node[i << 1 | 1].maxn );
82 node[i].sum = node[i << 1].sum + node[i << 1 | 1].sum;
83 }
84
85 void build( int i, int l, int r )
86 {
87 node[i].l = l, node[i].r = r;
88 if ( l == r )
89 {
90 node[i].maxn = node[i].sum = num[l];
91 return ;
92 }
93 int mid = ( l + r ) >> 1;
94 build( i << 1, l, mid );
95 build( i << 1 | 1, mid + 1, r );
96 pushup(i);
97 }
98
99 void update( int i, int pos, int val )
100 {
101 if ( node[i].l == pos && node[i].r == pos )
102 {
103 node[i].maxn = node[i].sum = val;
104 return ;
105 }
106 int mid = ( node[i].l + node[i].r ) >> 1;
107 if ( pos <= mid )
108 {
109 update( i << 1, pos, val );
110 }
111 else
112 {
113 update( i << 1 | 1, pos, val );
114 }
115 pushup(i);
116 }
117
118 int query_max( int i, int l, int r )
119 {
120 if ( node[i].l == l && node[i].r == r )
121 {
122 return node[i].maxn;
123 }
124 int mid = ( node[i].l + node[i].r ) >> 1;
125 if ( r <= mid )
126 {
127 return query_max( i << 1, l, r );
128 }
129 else if ( l > mid )
130 {
131 return query_max( i << 1 | 1, l, r );
132 }
133 else
134 {
135 return max( query_max( i << 1, l, mid ), query_max( i << 1 | 1, mid + 1, r ) );
136 }
137 }
138
139 int query_sum( int i, int l, int r )
140 {
141 if ( node[i].l == l && node[i].r == r )
142 {
143 return node[i].sum;
144 }
145 int mid = ( node[i].l + node[i].r ) >> 1;
146 if ( r <= mid )
147 {
148 return query_sum( i << 1, l, r );
149 }
150 else if ( l > mid )
151 {
152 return query_sum( i << 1 | 1, l, r );
153 }
154 else
155 {
156 return query_sum( i << 1, l, mid ) + query_sum( i << 1 | 1, mid + 1, r );
157 }
158 }
159
160 int tree_query_max( int x, int y )
161 {
162 int ans = INF;
163 while ( top[x] != top[y] )
164 {
165 if ( depth[top[x]] < depth[top[y]] )
166 {
167 swap( x, y );
168 }
169 ans = max( ans, query_max( 1, dfn[top[x]], dfn[x] ) );
170 x = fa[top[x]];
171 }
172 if ( depth[x] > depth[y] ) swap( x, y );
173 ans = max( ans, query_max( 1, dfn[x], dfn[y] ) );
174 return ans;
175 }
176
177 int tree_query_sum( int x, int y )
178 {
179 int ans = 0;
180 while ( top[x] != top[y] )
181 {
182 if ( depth[top[x]] < depth[top[y]] )
183 {
184 swap( x, y );
185 }
186 ans += query_sum( 1, dfn[top[x]], dfn[x] );
187 x = fa[top[x]];
188 }
189 if ( depth[x] > depth[y] ) swap( x, y );
190 ans += query_sum( 1, dfn[x], dfn[y] );
191 return ans;
192 }
193
194 int main ()
195 {
196 while ( scanf("%d", &n) != EOF )
197 {
198 init();
199 for ( int i = 1; i < n; i++ )
200 {
201 int u, v;
202 scanf("%d%d", &u, &v);
203 addEdge( u, v );
204 addEdge( v, u );
205 }
206 for ( int i = 1; i <= n; i++ )
207 {
208 scanf("%d", c + i);
209 }
210 dfs1( 1, -1, 1 );
211 dfs2( 1, 1 );
212 build( 1, 1, n );
213 char op[11];
214 int m, x, y;
215 scanf("%d", &m);
216 while ( m-- )
217 {
218 scanf("%s%d%d", op, &x, &y);
219 if ( op[1] == ‘M‘ )
220 {
221 printf("%d\n", tree_query_max( x, y ));
222 }
223 else if ( op[1] == ‘S‘ )
224 {
225 printf("%d\n", tree_query_sum( x, y ));
226 }
227 else
228 {
229 update( 1, dfn[x], y );
230 }
231 }
232 }
233 return 0;
234 }
时间： 2024-10-11 07:20:37