Link Cut Tree

刚开始写了个指针版。。调了一天然后放弃了。。

最后还是学了黄学长的板子！！

#include 
    
     #define INF 0x3f3f3f3f#define full(a, b) memset(a, b, sizeof a)using namespace std;typedef long long ll;inline int lowbit(int x){ return x & (-x); }inline int read(){    int X = 0, w = 0; char ch = 0;    while(!isdigit(ch)) { w |= ch == '-'; ch = getchar(); }    while(isdigit(ch)) X = (X << 3) + (X << 1) + (ch ^ 48), ch = getchar();    return w ? -X : X;}inline int gcd(int a, int b){ return a % b ? gcd(b, a % b) : b; }inline int lcm(int a, int b){ return a / gcd(a, b) * b; }template
     
      inline T max(T x, T y, T z){ return max(max(x, y), z); }template
      
       inline T min(T x, T y, T z){ return min(min(x, y), z); }template
       
        inline A fpow(A x, B p, C lyd){    A ans = 1;    for(; p; p >>= 1, x = 1LL * x * x % lyd)if(p & 1)ans = 1LL * x * ans % lyd;    return ans;}const int N = 300005;int ch[N][2], val[N], sum[N], rev[N], tot, fa[N], st[N], n, m;void newNode(int v){    val[++tot] = v, sum[tot] = v;    rev[tot] = ch[tot][0] = ch[tot][1] = fa[tot] = 0;}void reverse(int x){    swap(ch[x][0], ch[x][1]);    rev[x] ^= 1;}void push_up(int x){    sum[x] = val[x] ^ sum[ch[x][0]] ^ sum[ch[x][1]];}void push_down(int x){    if(rev[x]){        reverse(ch[x][0]), reverse(ch[x][1]);        //rev[x] ^= 1, rev[ch[x][0]] ^= 1, rev[ch[x][1]] ^= 1;        //swap(ch[x][0], ch[x][1]);        rev[x] ^= 1;    }}bool isRoot(int x){    return (!fa[x] || (ch[fa[x]][0] != x && ch[fa[x]][1] != x));}void rotate(int x){    int y = fa[x], z = fa[y], p = (ch[y][1] == x)^1;    ch[y][p^1] = ch[x][p], fa[ch[x][p]] = y;    if(!isRoot(y)) ch[z][ch[z][1] == y] = x;    fa[x] = z, ch[x][p] = y, fa[y] = x;    push_up(y), push_up(x);}void splay(int x){    int pos = 0; st[++pos] = x;    for(int i = x; !isRoot(i); i = fa[i]) st[++pos] = fa[i];    while(pos) push_down(st[pos --]);    while(!isRoot(x)){        int y = fa[x], z = fa[y];        if(!isRoot(y)){            if((ch[y][1] == x) ^ (ch[z][1] == y)) rotate(x);            else rotate(y);        }        rotate(x);    }}void access(int x){    for(int p = 0; x; p = x, x = fa[x])        splay(x), ch[x][1] = p, push_up(x);}void makeRoot(int x){    access(x), splay(x), reverse(x);}int findRoot(int x){    access(x), splay(x);    while(ch[x][0]) push_down(x), x = ch[x][0];    splay(x);    return x;}void split(int x, int y){    makeRoot(x), access(y), splay(y);}void link(int x, int y){    makeRoot(x);    if(findRoot(y) == x) return;    fa[x] = y;    push_up(y);}void cut(int x, int y){    makeRoot(x);    if(findRoot(y) != x || fa[y] != x || ch[y][0]) return;    ch[x][1] = fa[y] = 0;    push_up(x);}int main(){    n = read(), m = read();    for(int i = 1; i <= n; i ++){        int v = read(); newNode(v);    }    while(m --){        int opt = read(), x = read(), y = read();        if(opt == 0){            split(x, y); printf("%d\n", sum[y]);        }        else if(opt == 1){            link(x, y);        }        else if(opt == 2){            cut(x, y);        }        else if(opt == 3){            splay(x); val[x] = y;        }    }    return 0;}