D. Distinct Characters Queries （区间不同字符个数）

  1 #include <math.h>
  2 #include <stdio.h>
  3 #include <iostream>
  4 #include <algorithm>
  5 #include <string>
  6 #include <string.h>
  7 #include <vector>
  8 #include <map>
  9 #include <stack>
 10 #include <set>
 11 #include <random>
 12 
 13 
 14 #define LL long long
 15 
 16 const int maxn = 2e5 + 10;
 17 
 18 
 19 char s[maxn];
 20 int tree[26][maxn<<2];
 21 int t[26];
 22 
 23 
 24 void pushup(int nod) {
 25     for (int i=0;i<26;i++) {
 26         tree[i][nod] = tree[i][nod<<1] | tree[i][(nod<<1)+1];
 27     }
 28 }
 29 
 30 void build(int l,int r,int nod) {
 31     if (l == r) {
 32         tree[s[l]-'a'][nod] = 1;
 33         return ;
 34     }
 35     int mid = (l + r ) >> 1;
 36     build(l,mid,nod<<1);
 37     build(mid+1,r,(nod<<1)+1);
 38     pushup(nod);
 39 }
 40 
 41 void modify(int l,int r,int k,int pos,int v) {
 42     if (l == r) {
 43         for (int i=0;i<26;i++) {
 44             tree[i][k] = 0;
 45         }
 46         tree[v][k] = 1;
 47         return ;
 48     }
 49     int mid = (l + r) >> 1;
 50     if (pos <= mid) {
 51         modify(l,mid,k<<1,pos,v);
 52     } else {
 53         modify(mid+1,r,(k<<1)+1,pos,v);
 54     }
 55     pushup(k);
 56 }
 57 
 58 void query(int L,int R,int l,int r,int k) {
 59     if (L <= l && R >= r) {
 60         for (int i=0;i<26;i++) {
 61             t[i] |= tree[i][k];
 62         }
 63         return ;
 64     }
 65     int mid = (l + r) >> 1;
 66     if (L <= mid) {
 67         query(L,R,l,mid,k<<1);
 68     }
 69     if (R > mid) {
 70         query(L,R,mid+1,r,(k<<1)+1);
 71     }
 72 }
 73 
 74 
 75 
 76 int main() {
 77     std::cin >> s+1;
 78     int n = strlen(s+1);
 79     int T;
 80     int opt,x,y;
 81     char z;
 82     std::cin >> T;
 83     build(1,n,1);
 84     while (T--) {
 85         std::cin >> opt;
 86         if (opt == 1) {
 87             std::cin >> x >> z;
 88             modify(1,n,1,x,z-'a');
 89         }
 90         else if (opt == 2) {
 91             int temp = 0;
 92             std::cin >> x >> y;
 93             query(x,y,1,n,1);
 94             for (int i=0;i<26;i++) {
 95                 if (t[i]) {
 96                     ++temp;
 97                     t[i] = 0;
 98                 }
 99             }
100             printf("%d\n",temp);
101         }
102     }
103     return 0;
104 }