这还是道LCT的题，跟着czl做了好多LCT的题啊！没事，czl带我飞！加油，不错，挺顺利的。加油！1592毫秒， 第一次考虑了代码量， 我写这个花了 2800的代码长度， 然而czl只有1900， 代码简化还是很重要啊！
1 #include<cstdio> 2 #include<iostream> 3 #define lc c[k][0] 4 #define rc c[k][1] 5 #define rep(i,j,k) for(int i = j; i <= k; i++) 6 #define maxn 30233 7 using namespace std; 8 9 int c[maxn][2], pa[maxn], w[maxn], sum[maxn]; 10 bool rev[maxn]; 11 int read() 12 { 13 int s = 0,t = 1; char c = getchar(); 14 while( !isdigit(c) ){ 15 if( c == '-' ) t = -1; c = getchar(); 16 } 17 while( isdigit(c) ){ 18 s= s * 10+ c - '0'; c = getchar(); 19 } 20 return s * t; 21 } 22 23 bool root(int x) 24 { 25 int k = pa[x]; 26 return lc != x && rc != x; 27 } 28 29 void maintain(int k) 30 { 31 sum[k] = sum[lc] + sum[rc] + w[k]; 32 } 33 34 void rorate(int k) 35 { 36 int fa = pa[k], gfa = pa[fa]; 37 int l = c[fa][1] == k, r = l ^ 1; 38 if( !root(fa) ){ 39 c[gfa][c[gfa][1] == fa] = k; 40 } 41 pa[fa] = k, pa[k] = gfa, pa[c[k][r]] = fa; 42 c[fa][l] = c[k][r], c[k][r] = fa; maintain(fa), maintain(k); 43 } 44 45 void pushdown(int k) 46 { 47 if( rev[k] ){ 48 rev[k] ^= 1, rev[lc] ^= 1, rev[rc] ^= 1; 49 swap(lc,rc); 50 } 51 } 52 53 int q[maxn]; 54 void splay(int k) 55 { 56 int top = 0; q[++top] = k; 57 for(int x = k; !root(x); x = pa[x] ) 58 q[++top] = pa[x]; 59 while( top ) pushdown(q[top--]); 60 while( !root(k) ){ 61 int fa = pa[k], gfa = pa[fa]; 62 if( !root(fa) ){ 63 if( c[gfa][1] == fa ^ c[fa][1] == k ) rorate(k); 64 else rorate(fa); 65 } 66 rorate(k); 67 } 68 } 69 70 void access(int k) 71 { 72 for(int t = 0; k; t = k, k = pa[k]) 73 splay(k), rc = t, maintain(k); 74 } 75 76 void makeroot(int k) 77 { 78 access(k), splay(k), rev[k] ^= 1; 79 } 80 81 void link(int x,int y) 82 { 83 makeroot(x), pa[x] = y; 84 } 85 86 void split(int x,int y) 87 { 88 makeroot(x), access(y), splay(y); c[y][0] = pa[x] = 0; 89 maintain(y); 90 } 91 92 int find(int k) 93 { 94 access(k), splay(k); 95 while( lc ) k = lc; 96 return k; 97 } 98 99 int query(int x,int y) 100 { 101 makeroot(x), access(y), splay(y); return sum[y]; 102 } 103 104 int main() 105 { 106 int n = read(); 107 rep(i,1,n) w[i] = read(); char c[20]; 108 int m = read(); 109 rep(i,1,m){ 110 scanf("%s", c); 111 if( c[0] == 'b' ) { 112 int x = read(), y = read(); 113 int kx = find(x), ky = find(y); 114 if( kx != ky ) { 115 puts("yes"); 116 link(x,y); 117 } 118 else puts("no"); 119 } 120 if( c[0] == 'e' ){ 121 int x = read(), y = read(); 122 int kx = find(x), ky = find(y); 123 if( kx != ky ) puts("impossible"); 124 else printf("%d ", query(x,y)); 125 } 126 if( c[0] == 'p' ){ 127 int x = read(), y = read(); 128 splay(x); w[x] = y; maintain(x); 129 } 130 } 131 return 0; 132 }