21 lines
386 B
C++
21 lines
386 B
C++
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template<typename T>
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struct BIT {
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int n;
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vector<T> c;
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BIT(size_t n) : n(n), c(n + 1) {}
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void add(size_t i, const T& k) {
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while (i <= n) {
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c[i] += k;
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i += lowbit(i);
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}
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}
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T getsum(size_t i) {
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T res = {};
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while (i) {
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res += c[i];
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i -= lowbit(i);
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}
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return res;
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}
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};
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