Created
September 6, 2016 03:44
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dynamic median
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//Get median of a sequence in O(log(n)) | |
void balance() { | |
while (abs((int) (minHeap.size() - maxHeap.size())) > 1) { | |
if (minHeap.size() > maxHeap.size()) { | |
int tmp = minHeap.top(); | |
minHeap.pop(); | |
maxHeap.push(tmp); | |
} else { | |
int tmp = maxHeap.top(); | |
maxHeap.pop(); | |
minHeap.push(tmp); | |
} | |
} | |
} | |
int median_retrieve(void) { | |
if (minHeap.empty() && maxHeap.empty()) return 0; | |
if (minHeap.size() == maxHeap.size()) { | |
return min(minHeap.top(), maxHeap.top()); | |
} else { | |
if (minHeap.size() > maxHeap.size()) { | |
return minHeap.top(); | |
} else { | |
return maxHeap.top(); | |
} | |
} | |
} | |
void median_insert(int x) { | |
if (x > median_retrieve()) { | |
minHeap.push(x); | |
} else { | |
maxHeap.push(x); | |
} | |
balance(); | |
} |
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