29 lines
676 B
C++
29 lines
676 B
C++
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template<typename T>
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struct BIT2d {
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int n, m;
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vector<vector<T>> c;
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BIT2d(size_t n, size_t m) : n(n), m(m), c(n + 1, vector<T>(m + 1)) {}
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void add(size_t i, size_t j, const T& k) {
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while (i <= n) {
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size_t j1 = j;
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while (j1 <= m) {
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c[i][j1] += k;
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j1 += lowbit(j1);
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}
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i += lowbit(i);
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}
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}
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T getsum(size_t i, size_t j) {
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T res = {};
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while (i) {
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size_t j1 = j;
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while (j1) {
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res += c[i][j1];
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j1 -= lowbit(j1);
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}
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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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