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
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
/* 2021
 * Maciej Szeptuch
 */
#include <cstdint>
#include <cstdio>
#include <functional>
#include <map>
#include <unordered_map>
#include <utility>
#include <vector>

const int MAX_LENGTH = 524288;
char word[MAX_LENGTH];
int as;
int bs;
int cs;
long long int count;

struct hash_pair
{
    size_t operator()(const std::pair<int, int> &p) const
    {
        auto first = std::hash<int>{}(p.first);
        auto second = std::hash<int>{}(p.second);
        return first ^ (second + 0x9e3779b9 + (first << 6) + (first >> 2));
    }
};

// typedef std::map<std::pair<int, int>, int> Map;
typedef std::unordered_map<std::pair<int, int>, int, hash_pair> Map;

Map abc; // a == b == c
Map ab; // a == b && c == 0
Map ac; // a == c && b == 0
Map bc; // b == c && a == 0
Map a; // b == c == 0
Map b; // a == c == 0
Map c; // a == b == 0

int main(void)
{
    scanf("%s", word);

    abc[{0, 0}] = 1;
    ab[{0, 0}] = 1;
    ac[{0, 0}] = 1;
    bc[{0, 0}] = 1;
    a[{0, 0}] = 1;
    b[{0, 0}] = 1;
    c[{0, 0}] = 1;

    for(int w = 1; word[w - 1]; ++w)
    {
        as += (word[w - 1] == 'a');
        bs += (word[w - 1] == 'b');
        cs += (word[w - 1] == 'c');

        auto _abc = std::make_pair(as - bs, as - cs);
        auto _ab = std::make_pair(cs, as - bs);
        auto _ac = std::make_pair(bs, as - cs);
        auto _bc = std::make_pair(as, bs - cs);
        auto _a = std::make_pair(bs, cs);
        auto _b = std::make_pair(as, cs);
        auto _c = std::make_pair(as, bs);

        count += abc[_abc] + ab[_ab] + ac[_ac] + bc[_bc] + a[_a] + b[_b] + c[_c];
        abc[_abc] += 1;
        ab[_ab] += 1;
        ac[_ac] += 1;
        bc[_bc] += 1;
        a[_a] += 1;
        b[_b] += 1;
        c[_c] += 1;
    }

    printf("%lld\n", count);
    return 0;
}