Subpalindromes, palindrome

Subpalindromes, palindrome

Question Link

• Question:
  Give a string (length cannot exceed 1 E5), m operations (m cannot exceed 1 E5), each operation: 1. Query [l, r] whether it is a text string. 2. Change the p position to v.
• Analysis:
  This topic involves a processing method of the return string: To determine whether the forward and reverse are the same, a simple method is to use Hash to identify. The subsequent problems are vertex update and query interval, which are solved by the line segment tree.

const int MAXN = 410000;const int SEED = 13331;ULL f[MAXN];char ipt[MAXN], t[110];#define lson rt << 1#define rson rt << 1 | 1struct Node{    int l, r, m;    ULL vl, vr;} nd[MAXN << 2], tt;void merge(Node& ret, Node& l, Node& r, int L, int M, int R){    ret.vl = r.vl * f[M - L + 1] + l.vl;    ret.vr = l.vr * f[R - M] + r.vr;}void pushup(int rt){    merge(nd[rt], nd[lson], nd[rson], nd[rt].l, nd[rt].m, nd[rt].r);}void build(int l, int r, int rt){    nd[rt].l = l; nd[rt].r = r; nd[rt].m = (r + l) >> 1;    if (l == r)    {        nd[rt].vl = nd[rt].vr = ipt[l - 1];    }    else    {        build(l, nd[rt].m, lson);        build(nd[rt].m + 1, r, rson);        pushup(rt);    }}void update(int p, int v, int rt){    if (nd[rt].l == nd[rt].r)    {        nd[rt].vl = nd[rt].vr = v;    }    else    {        if (p <= nd[rt].m)            update(p, v, lson);        else            update(p, v, rson);        pushup(rt);    }}Node query(int L, int R, int rt){    if (L <= nd[rt].l && nd[rt].r <= R)        return nd[rt];    if (R <= nd[rt].m)        return query(L, R, lson);    else if (L > nd[rt].m)        return query(L, R, rson);    Node tl = query(L, R, lson);    Node tr = query(L, R, rson);    Node ret;    merge(ret, tl, tr, max(L, nd[rt].l), nd[rt].m, min(R, nd[rt].r));    return ret;}int main(){    f[0] = 1;    FF(i, 1, MAXN)        f[i] = f[i - 1] * SEED;    int n;    while (~RS(ipt))    {        build(1, strlen(ipt), 1);        RI(n);        REP(i, n)        {            RS(t);            if (t[0] == 'p')            {                int a, b;                RII(a, b);                tt = query(a, b, 1);                printf("%s\n", tt.vl == tt.vr ? "Yes" : "No");            }            else            {                int p; char v;                scanf("%d %c", &p, &v);                update(p, v, 1);            }        }    }    return 0;}

How to read Palindromes?

Pal-in-dromes: Can you tell me what it means? Follow the feeling to read

C ++ programming for return and prime numbers

Not difficult.
It only requires no array, no string
A function must be used. The function must be placed in the header file and must be called.

No need to use arrays...
Create a header file and create two functions in it. Both functions have only one parameter. The returned value can be 0/1 or another.
Function 1 Implementation: Check whether a number is a return number. Use the remainder calculation method to check whether the first and last bits are the same. If they are different, the function returns a number, check whether the input parameter is a return value.
Function 2 Implementation: Check whether a number is a prime number. I don't need to talk about this.

Finally, create the main function to call the original header file.
A loop in the main function, 1--N
You can use two functions to view them one by one. The values that meet the conditions are the required numbers.

Finished ..... If arrays are used, the idea may be clearer.