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| 1 | +#encoding:utf-8 |
| 2 | +#Created by Liang Sun on May, 6, 2013 |
| 3 | +class SegmentTree(object): |
| 4 | + def _init(self, start, end): |
| 5 | + self.data[(start, end)] = 0 |
| 6 | + if start < end: |
| 7 | + mid = start + (end - start) / 2 |
| 8 | + self._init(start, mid) |
| 9 | + self._init(mid+1, end) |
| 10 | + |
| 11 | + def __init__(self, start, end): |
| 12 | + self.start = start |
| 13 | + self.end = end |
| 14 | + self.data = {} |
| 15 | + self._init(start, end) |
| 16 | + |
| 17 | + def add(self, start, end, weight): |
| 18 | + if start < self.start or end > self.end: |
| 19 | + return False |
| 20 | + self._add(start, end, weight, self.start, self.end) |
| 21 | + return True |
| 22 | + |
| 23 | + def _add(self, start, end, weight, in_start, in_end): |
| 24 | + if in_start == in_end: |
| 25 | + self.data[(in_start, in_end)] += weight |
| 26 | + return |
| 27 | + |
| 28 | + mid = in_start + (in_end - in_start) / 2 |
| 29 | + if mid >= end: |
| 30 | + self._add(start, end, weight, in_start, mid) |
| 31 | + elif mid+1 <= start: |
| 32 | + self._add(start, end, weight, mid+1, in_end) |
| 33 | + else: |
| 34 | + self._add(start, mid, weight, in_start, mid) |
| 35 | + self._add(mid+1, end, weight, mid+1, in_end) |
| 36 | + self.data[(in_start, in_end)] = max(self.data[(in_start, mid)], self.data[(mid+1, in_end)]) |
| 37 | + |
| 38 | + def query(self, start, end): |
| 39 | + return self._query(start, end, self.start, self.end) |
| 40 | + |
| 41 | + def _query(self, start, end, in_start, in_end): |
| 42 | + if start == in_start and end == in_end: |
| 43 | + ans = self.data[(start, end)] |
| 44 | + else: |
| 45 | + mid = in_start + (in_end - in_start) / 2 |
| 46 | + if mid >= end: |
| 47 | + ans = self._query(start, end, in_start, mid) |
| 48 | + elif mid+1 <= start: |
| 49 | + ans = self._query(start, end, mid+1, in_end) |
| 50 | + else: |
| 51 | + ans = max(self._query(start, mid, in_start, mid), |
| 52 | + self._query(mid+1, end, mid+1, in_end)) |
| 53 | + #print start, end, in_start, in_end, ans |
| 54 | + return ans |
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