Algorithm
Ilya the Lion wants to help all his friends with passing exams. They need to solve the following problem to pass the IT exam.
You've got string s = s1s2... sn (n is the length of the string), consisting only of characters "." and "#" and m queries. Each query is described by a pair of integers li, ri (1 ≤ li < ri ≤ n). The answer to the query li, ri is the number of such integers i (li ≤ i < ri), that si = si + 1.
Ilya the Lion wants to help his friends but is there anyone to help him? Help Ilya, solve the problem.
The first line contains string s of length n (2 ≤ n ≤ 105). It is guaranteed that the given string only consists of characters "." and "#".
The next line contains integer m (1 ≤ m ≤ 105) — the number of queries. Each of the next m lines contains the description of the corresponding query. The i-th line contains integers li, ri (1 ≤ li < ri ≤ n).
Print m integers — the answers to the queries in the order in which they are given in the input.
......
4
3 4
2 3
1 6
2 6
1
1
5
4
#..###
5
1 3
5 6
1 5
3 6
3 4
1
1
2
2
0
Code Examples
#1 Code Example with C++ Programming
Code -
C++ Programming
#include <iostream>
#include <string>
using namespace std;
int const N = 1e5 + 1;
int cum[N];
int main() {
string s;
cin >> s;
cum[0] = 0;
for(int i = 1; i < s.length(); i++) {
if(s[i] == s[i-1]) cum[i] = cum[i-1] + 1;
else cum[i] = cum[i-1];
}
int q;
cin >> q;
int a, b;
while(q--) {
cin >> a >> b;
a--; b--;
cout << cum[b] - cum[a] << endl;
}
}Input
4
3 4
2 3
1 6
2 6
Output
1
5
4
Demonstration
Codeforces Solution-Ilya and Queries-Solution in C, C++, Java, Python