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#include "leetcode.h"
class Solution {
public:
int longestPath(vector<int> &parent, string s) {
int n = parent.size(), ans = 1;
queue<int> q;
vector<int> cnt(n), top1(n, 1), top2(n, 1);
for (int i = 1; i < n; ++i)
++cnt[parent[i]];
for (int i = 1; i < n; ++i)
if (cnt[i] == 0)
q.push(i);
while (!q.empty() && q.front() != 0) {
int i = q.front(), p = parent[i];
q.pop();
if (int len = 1 + (s[i] != s[p] ? top1[i] : 0); top1[p] <= len) {
top2[p] = top1[p];
top1[p] = len;
} else
top2[p] = max(top2[p], len);
if (--cnt[p] == 0) {
q.push(p);
ans = max(ans, top1[p] + top2[p] - 1);
}
}
return ans;
}
};
int main() {
Solution obj;
vector<int> parent1 = {-1, 0, 0, 1, 1, 2}, parent2 = {-1, 0, 0, 0};
cout << obj.longestPath(parent1, "abacbe") << endl; // expect: 3
cout << obj.longestPath(parent2, "aabc") << endl; // expect: 3
}
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