【HYSBZ】1036 树的统计Count

  1 #include<cstdio>

  2 #include<cstring>

  3 #include<queue>

  4 #include<iostream>

  5 #include<algorithm>

  6 #define oo 0x7FFFFFFF

  7 #define MAXN 30010

  8 #define MAXM 60010

  9 using namespace std;

 10 int first[MAXN], next[MAXM], v[MAXM], e;

 11 bool vis[MAXN];

 12 struct LCT {

 13     int bef[MAXN];

 14     int next[MAXN][2], pre[MAXN], key[MAXN], sum[MAXN], val[MAXN];

 15     void Init() {

 16         memset(next, 0, sizeof(next));

 17         memset(pre, 0, sizeof(pre));

 18         val[0] = -oo;

 19         sum[0] = 0;

 20     }

 21     inline void PushUp(int x) {

 22         sum[x] = key[x] + sum[next[x][0]] + sum[next[x][1]];

 23         val[x] = max(key[x], max(val[next[x][0]], val[next[x][1]]));

 24     }

 25     void Rotate(int x, int kind) {

 26         int y, z;

 27         y = pre[x];

 28         z = pre[y];

 29         next[y][!kind] = next[x][kind];

 30         pre[next[x][kind]] = y;

 31         next[z][next[z][1] == y] = x;

 32         pre[x] = z;

 33         next[x][kind] = y;

 34         pre[y] = x;

 35         PushUp(y);

 36     }

 37     void Splay(int x) {

 38         int rt;

 39         for (rt = x; pre[rt]; rt = pre[rt])

 40             ;

 41         if (rt != x) {

 42             bef[x] = bef[rt];

 43             bef[rt] = 0;

 44             while (pre[x]) {

 45                 if (next[pre[x]][0] == x)

 46                     Rotate(x, 1);

 47                 else

 48                     Rotate(x, 0);

 49             }

 50             PushUp(x);

 51         }

 52     }

 53     void Access(int x) {

 54         int father;

 55         for (father = 0; x; x = bef[x]) {

 56             Splay(x);

 57             pre[next[x][1]] = 0;

 58             bef[next[x][1]] = x;

 59             next[x][1] = father;

 60             pre[father] = x;

 61             bef[father] = 0;

 62             father = x;

 63             PushUp(x);

 64         }

 65     }

 66     void Change(int x, int val) {

 67         key[x] = val;

 68         Splay(x);

 69     }

 70     int Query(int x, int y, bool flag) {

 71         Access(y);

 72         for (y = 0; x; x = bef[x]) {

 73             Splay(x);

 74             if (!bef[x]) {

 75                 if (flag)

 76                     return max(key[x], max(val[next[x][1]], val[y]));

 77                 else

 78                     return key[x] + sum[next[x][1]] + sum[y];

 79             }

 80             pre[next[x][1]] = 0;

 81             bef[next[x][1]] = x;

 82             next[x][1] = y;

 83             pre[y] = x;

 84             bef[y] = 0;

 85             y = x;

 86             PushUp(x);

 87         }

 88         return 0;

 89     }

 90 } lct;

 91 int INT() {

 92     char ch;

 93     int res;

 94     bool neg;

 95     while (ch = getchar(), !isdigit(ch) && ch != '-')

 96         ;

 97     if (ch == '-') {

 98         neg = true;

 99         res = 0;

100     } else {

101         neg = false;

102         res = ch - '0';

103     }

104     while (ch = getchar(), isdigit(ch))

105         res = res * 10 + ch - '0';

106     return neg ? -res : res;

107 }

108 char CHAR() {

109     char ch, res;

110     while (ch = getchar(), !isalpha(ch))

111         ;

112     while (ch = getchar(), isalpha(ch))

113         res = ch;

114     return res;

115 }

116 inline void AddEdge(int x, int y) {

117     v[e] = y;

118     next[e] = first[x];

119     first[x] = e++;

120 }

121 void BFS(int x) {

122     int i, y;

123     queue<int> q;

124     memset(vis, false, sizeof(vis));

125     vis[x] = true;

126     q.push(x);

127     while (!q.empty()) {

128         x = q.front();

129         q.pop();

130         for (i = first[x]; i != -1; i = next[i]) {

131             y = v[i];

132             if (!vis[y]) {

133                 lct.bef[y] = x;

134                 vis[y] = true;

135                 q.push(y);

136             }

137         }

138     }

139 }

140 int main() {

141     char ch;

142     int n, i, q, x, y;

143     while (~scanf("%d", &n)) {

144         lct.Init();

145         memset(first, -1, sizeof(first));

146         for (e = 0, i = 1; i < n; i++) {

147             x = INT(), y = INT();

148             AddEdge(x, y);

149             AddEdge(y, x);

150         }

151         for (i = 1; i <= n; i++)

152             lct.key[i] = INT();

153         BFS(1);

154         q = INT();

155         while (q--) {

156             ch = CHAR(), x = INT(), y = INT();

157             if (ch == 'E')

158                 lct.Change(x, y);

159             else if (ch == 'X')

160                 printf("%d\n", lct.Query(x, y, true));

161             else

162                 printf("%d\n", lct.Query(x, y, false));

163         }

164     }

165     return 0;

166 }