## Descripion

## Submission

class Solution {
public:
int largestVariance(string s) {
int ret = 0;
for(int i = 0; i < 26; ++i) {
char ch1 = 'a' + i;
for(int j = 0; j < 26; ++j) {
if(i == j) continue;
vector<int> arr;
char ch2 = 'a' + j;
for(char ch: s) {
if(ch == ch1) arr.push_back(1);
else if(ch == ch2) arr.push_back(-1);
}
int t = arr.size();
if(!t) continue;
vector<int> dp1(t);
dp1[0] = arr[0];
for(int k = 1; k < t; ++k) {
dp1[k] = max(dp1[k-1] + arr[k], arr[k]);
}
vector<int> dp2(t);
dp2[t-1] = arr[t-1];
for(int k = t - 2; k >= 0; --k) {
dp2[k] = max(dp2[k+1] + arr[k], arr[k]);
}
for(int k = 0; k < t; ++k) {
if(arr[k] == -1) ret = max(ret, dp1[k] + dp2[k] - arr[k]);
}
}
}
return ret;
}
};
// [1, 1, 1, 1, {-1], 1} -1, 1, -1