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LongestConsecutiveSequence.cpp
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LongestConsecutiveSequence.cpp
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// https://oj.leetcode.com/problems/longest-consecutive-sequence/
class Solution {
public:
int longestConsecutive(vector<int> &num) {
if (0 == num.size()) {
return 0;
}
unordered_set<int> numset;
for (vector<int>::iterator iter = num.begin(); iter != num.end(); ++iter) {
numset.insert(*iter);
}
unordered_set<int>::iterator iter = numset.begin();
int result = 0, cur_val = 0, find_val_right = 0, find_val_left = 0, cur_len = 0;
while (iter != numset.end()) {
cur_val = *iter;
numset.erase(cur_val);
cur_len = 1;
find_val_right = cur_val + 1;
while (numset.find(find_val_right) != numset.end()) {
numset.erase(find_val_right++);
cur_len++;
}
find_val_left = cur_val - 1;
while (numset.find(find_val_left) != numset.end()) {
numset.erase(find_val_left--);
cur_len++;
}
if (cur_len > result) {
result = cur_len;
}
iter = numset.begin();
}
return result;
}
};