1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
#define make_pair mp
#define emplace_back pb
#include <bits/stdc++.h>
using namespace std;
mt19937 mt_rand(time(0));
const int N = 3e5 + 5;
int n, a, b, c;
char s[N];
map<int, map<int, int>> m;
map<int, int> m2;
long long res;
int main() {
	scanf("%s", &s);
    m[0][0] = 1;
    while(s[n]) {
        if(s[n] == 'a') {
            a++;
        } else if(s[n] == 'b') {
            b++;
        } else {
            c++;
        }
        res += m[a-b][a-c];
        m[a-b][a-c]++;
        n++;
    }
    int first = 0;
    for(int i=1;i<=n;i++) {
        if(s[i] != s[i-1]) {
            long long num = i - first;
            num *= (num + 1);
            num /= 2;
            res += num;
            first = i;
        }
    }
    char cc = 'a' - 1;
    char ccc = 'a';
    for(int j=0;j<3;j++) {
        cc++;
        ccc++;
        if(ccc > 'c') ccc = 'a';
        m2.clear();
        m2[0] = 1;
        int sub = 0;
        for(int i=0;i<n;i++) {
            if(s[i] == cc) {
                m2.clear();
                m2[0] = 0;
                sub = 0;
            }
            if(s[i] == ccc) sub++;
            else sub--;
            res += m2[sub];
            m2[sub]++;
        }
    }
    printf("%lld\n", res);
	return 0;
}