UVA 11996 Splay + LCP + Hash + 区间翻转 插入 删除

【题意】给出一个长度为n的01串，有m个操作。操作有以下几种：

              1 p c在第p个字符后插入c

              2 p    删除第p个字符

              3 p1 p2 翻转p1到p2的字符串

              4 p1 p2 求从p1开始和p2开始的两个后缀的LCP

【解题方法】

             参见白书。利用字符串hash，可以维护一个区间的字符串的hash值，利用伸展树可以轻松的完成前3种操作，对于操作4，二分一下长度，将取出的两个串的hash值进行比较，就能判断是否相同。

【PS】这题有点恶心，在LCP提取区间的时候，把Rotateto写成了Rotate，查了半天错才知道。

【代码君】

////Created by just_sort 2016/10/15//Copyright (c) 2016 just_sort.All Rights Reserved//#include <set>#include <map>#include <queue>#include <stack>#include <cmath>#include <cstdio>#include <cstdlib>#include <cstring>#include <iostream>#include <algorithm>using namespace std;typedef long long LL;typedef unsigned long long uLL;const int pp = 239641;const int maxn = 555555;uLL p[maxn],Hash[maxn][2];char s[maxn];int ch[maxn][2],pre[maxn],val[maxn],sz[maxn],rev[maxn],root,tot;void Treaval(int x) {    if(x) {        Treaval(ch[x][0]);        printf("结点%2d:左儿子 %2d 右儿子 %2d 父结点 %2d size = %2d ,val = %2d\n",x,ch[x][0],ch[x][1],pre[x],sz[x],val[x]);        Treaval(ch[x][1]);    }}void debug() {printf("%d\n",root);Treaval(root);}void Newnode(int &rt,int fa,int k){    rt = ++tot;    ch[rt][0] = ch[rt][1] = rev[rt] = 0;    sz[rt] = 1;    pre[rt] = fa;    Hash[rt][0] = Hash[rt][1] = val[rt] = k;}void pushup(int rt){    sz[rt] = sz[ch[rt][0]] + sz[ch[rt][1]] + 1;    int len = sz[ch[rt][0]];    Hash[rt][0] = Hash[ch[rt][0]][0] + val[rt]*p[len] + Hash[ch[rt][1]][0]*p[len+1];    len = sz[ch[rt][1]];    Hash[rt][1] = Hash[ch[rt][1]][1] + val[rt]*p[len] + Hash[ch[rt][0]][1]*p[len+1];}void f(int rt){    if(!rt) return ;    swap(ch[rt][0], ch[rt][1]);    swap(Hash[rt][0], Hash[rt][1]);    rev[rt] ^= 1;}void pushdown(int rt){    if(rev[rt]){        f(ch[rt][0]);        f(ch[rt][1]);        rev[rt] = 0;    }}void Rotate(int x,int kind){    int y = pre[x];    pushdown(y); pushdown(x);    ch[y][kind^1] = ch[x][kind];    pre[ch[x][kind]] = y;    if(pre[y]) ch[pre[y]][ch[pre[y]][1] == y] = x;    pre[x] = pre[y];    ch[x][kind] = y;    pre[y] = x;    pushup(y);}void Splay(int r,int goal){    pushdown(r);    while(pre[r]!=goal)    {        if(pre[pre[r]]==goal)        {            Rotate(r,ch[pre[r]][0]==r);            pushdown(pre[r]);            pushdown(r);        }        else        {            pushdown(pre[pre[r]]);            pushdown(pre[r]);            pushdown(r);            int y=pre[r];            int kind=(ch[pre[y]][0]==y);            if(ch[y][kind]==r)            {                Rotate(r,!kind);                Rotate(r,kind);            }            else            {                Rotate(y,kind);                Rotate(r,kind);            }        }    }    pushup(r);    if(goal==0) root=r;}void RotateTo(int k, int goal){    int rt = root;    pushdown(rt);    while(sz[ch[rt][0]] != k)    {        if(sz[ch[rt][0]] > k)            rt = ch[rt][0];        else{            k -= (sz[ch[rt][0]] + 1);            rt = ch[rt][1];        }        pushdown(rt);    }    Splay(rt,goal);}void Insert(int k, int c){    RotateTo(k, 0);    RotateTo(k+1, root);    int rt = ch[root][1];    Newnode(ch[rt][0], rt, c);    pushup(rt);    pushup(root);}void Delete(int p){    RotateTo(p-1, 0);    RotateTo(p+1, root);    int rt  =ch[root][1];    ch[rt][0] = 0;    pushup(rt);    pushup(root);}void Reverse(int L, int R){    RotateTo(L-1, 0);    RotateTo(R+1, root);    f(ch[ch[root][1]][0]);    pushup(ch[root][1]);    pushup(root);}bool judge(int x,int y,int len){    uLL xval, yval;    RotateTo(x-1, 0);    if(sz[ch[root][1]] - 1 < len) return 0;    RotateTo(x+len, root);    int rt = ch[ch[root][1]][0];    xval = Hash[rt][rev[rt]];    RotateTo(y-1, 0);    if(sz[ch[root][1]] - 1 < len) return 0;    RotateTo(y+len, root);    rt = ch[ch[root][1]][0];    yval = Hash[rt][rev[rt]];    return xval == yval;}int Lcp(int x,int y){    int L = 1, R = sz[root] - 1;    if(!judge(x, y, 1)) return 0;    while(R - L > 1)    {        int mid = (L + R)>>1;        if(judge(x, y, mid)) L = mid;        else R = mid;    }    return L;}void Build(int l, int r,int &rt, int fa){    if(l > r) return;    int m = (l + r)>>1;    Newnode(rt, fa, s[m] - '0');    Build(l, m-1, ch[rt][0], rt);    Build(m+1, r, ch[rt][1], rt);    pushup(rt);}void Init(int n){    ch[0][0] = ch[0][1] = sz[0] = 0;    Hash[0][0] = Hash[0][1] = 0;    rev[0] = pre[0] = val[0] = 0;    root = tot = 0;    Newnode(root, 0, 0);    Newnode(ch[root][1], root, 0);    Build(0, n-1, ch[ch[root][1]][0], ch[root][1]);    pushup(ch[root][1]);    pushup(root);}int main(){    p[0] = 1;    for(int i = 1; i < maxn; i++) p[i] = p[i-1] * pp;    int n, m;    while(scanf("%d%d",&n,&m) != EOF)    {        scanf("%s", s);        Init(n);        //debug();        int op, p1, p2, c;        for(int i = 1; i <= m; i++)        {            scanf("%d%d", &op, &p1);            if(op == 1)            {                scanf("%d", &c);                Insert(p1, c);                //debug();            }            else if(op == 2){                Delete(p1);                //debug();            }            else if(op == 3){                scanf("%d", &p2);                Reverse(p1,p2);                //debug();            }            else{                scanf("%d", &p2);                int ans = Lcp(p1, p2);                printf("%d\n", ans);            }        }    }    return 0;}