AC dreamoj 1011 Tree Array +hash maintain the prefix of the string and

http://acdream.info/problem?pid=1019

Problem Description

We have a long long string, and we'll have the kinds of operation on it.

C i y : Change the ith letter to y.
Q i j : Check whether the substring from ith to jth letter is a palindrome.

Input

There is multiple test cases.

The first line contains a string whose length was not large than 1,000,000.

The next line contains a integer N indicating the number of operations.

The next N lines Each lines contains a operation.

All letters in the input is lower-case.

Outputfor each query operation, output " Yes"If the corresponding substring is a palindrome, otherwise output" No". Sample Input

aaaaa4q 1 5C 2 BQ 1 5Q 1 3

Sample Output

Yesnoyes

/**acdreamoj 1019 Tree Array +hash maintain the prefix and title of the string: Given a string, a single point of update, interval query whether the interval is a palindrome string. Problem-solving ideas: Hash is x1 * p^1+ x2*p^2 +x3*p^3 ... you can maintain prefixes and maintain two strings in a tree-like array, one is a positive string, and the other is crossdress for comparison. The hash value of the string interval s[l~r] is sum (s[r]-s[l-1])/hash[l-1];*/#include <stdio.h> #include <string.h> #include < Iostream> #include <algorithm>using namespace std;typedef unsigned long long ll;const int Maxn=1000010;const int seed=13;    LL Hash[maxn],c[2][maxn];char s[maxn];int len;void init () {hash[0]=1; for (int i=1;i<maxn;i++) hash[i]=hash[i-1]*seed;} int lowbit (int x) {return x& (-X);}        void Add (int i,int x,ll POS) {while (X<=len) {c[i][x]+=pos;    X+=lowbit (x);    }}ll sum (int i,int x) {LL ans=0;        while (x) {ans+=c[i][x];    X-=lowbit (x); } return ans; LL gethash (int i,int l,int r) {return sum (i,r)-sum (I,L-1);}     int main () {init ();         while (~SCANF ("%s", s+1)) {memset (c,0,sizeof (C));         Len=strlen (s+1);   for (int i=1;i<=len;i++)      {Add (0,i, (s[i]-' a ') *hash[i]);         Add (1,len+1-i, (s[i]-' a ') *hash[len+1-i]);         } int T;         Cin >> T;             while (t--) {char c[5];             scanf ("%s", c);                 if (c[0]== ' C ') {char b[5];                 int A;                 scanf ("%d%s", &a,b);                 Add (0,a, (B[0]-s[a]) *hash[a]);                 Add (1,len+1-a, (B[0]-s[a]) *hash[len+1-a]);             S[A]=B[0];                 } else {int l,r;                 scanf ("%d%d", &l,&r);                 if (Gethash (0,l,r) *hash[len-r]==gethash (1,len+1-r,len+1-l) *HASH[L-1])//use cross multiplication to replace the multiply puts ("yes");             Else puts ("no"); }}} return 0;}

AC dreamoj 1011 Tree Array +hash maintain the prefix of the string and