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32 lines
552 B
C++
32 lines
552 B
C++
#include <iostream>
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#include <map>
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using namespace std;
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const int n = 2000000000;
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void add(map<int, int> &t, int i, int value) {
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for (; i < n; i |= i + 1)
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t[i] += value;
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}
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// sum[0,i]
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int sum(map<int, int> &t, int i) {
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int res = 0;
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for (; i >= 0; i = (i & (i + 1)) - 1)
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if (t.count(i)) res += t[i];
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return res;
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}
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// Usage example
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int main() {
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map<int, int> t;
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add(t, 0, 4);
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add(t, 1, 5);
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add(t, 2, 5);
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add(t, 2, 5);
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cout << (4 == sum(t, 0)) << endl;
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cout << (19 == sum(t, 2)) << endl;
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cout << (19 == sum(t, 1000000000)) << endl;
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}
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