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#include "leetcode.h"
class Solution {
public:
vector<int> sumOfDistancesInTree(int n, vvd(int) & edges) {
tree.resize(n);
ans.assign(n, 0);
count.assign(n, 1);
for (auto e : edges) {
tree[e[0]].insert(e[1]);
tree[e[1]].insert(e[0]);
}
dfs(0, -1);
dfs2(0, -1);
return ans;
}
private:
vector<unordered_set<int>> tree;
vector<int> ans, count;
void dfs(int root, int pre) {
for (auto i : tree[root]) {
if (i == pre)
continue;
dfs(i, root);
count[root] += count[i];
ans[root] += ans[i] + count[i];
}
}
void dfs2(int root, int pre) {
for (auto i : tree[root]) {
if (i == pre)
continue;
ans[i] = ans[root] - count[i] + count.size() - count[i];
dfs2(i, root);
}
}
};
int main() {
Solution obj;
vvd(int) edges = {{0, 1}, {0, 2}, {2, 3}, {2, 4}, {2, 5}};
for (auto i : obj.sumOfDistancesInTree(6, edges))
cout << i << ' '; // expect: 8 12 6 10 10 10
}
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