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 }
