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Update fenwick_tree_2d.cpp

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Anthony Wang 2019-07-26 15:40:54 -05:00 committed by GitHub
parent a5b7c15230
commit b0bc5023ca
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1 changed files with 14 additions and 14 deletions
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Data Structures/fenwick_tree_2d.cpp
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@ -1,21 +1,21 @@
class fenwick_tree_2d {
private: int N, M, vector<vector<int>> FT;
public:
fenwick_tree_2d(int n, int m) {
N = n + 1, M = m + 1;
FT.resize(N, 0);
for (int i = 0; i < N; i++) FT[i].resize(M, 0);
}
void update(int x, int y, int val) {
for (int i = x; i < N; i += i & -i) {
for (int j = y; j < M; j += j & -j) FT[i][j] += val;
fenwick_tree_2d(int n, int m) {
N = n + 1, M = m + 1;
FT.resize(N, 0);
for (int i = 0; i < N; i++) FT[i].resize(M, 0);
}
void update(int x, int y, int val) {
for (int i = x; i < N; i += i & -i) {
for (int j = y; j < M; j += j & -j) FT[i][j] += val;
}
}
int query(int x, int y) {
int ret = 0;
for (int i = x; i > 0; i -= i & -i) {
for (int j = y; j > 0; j -= j & -j) ret += FT[i][j];
int query(int x, int y) {
int ret = 0;
for (int i = x; i > 0; i -= i & -i) {
for (int j = y; j > 0; j -= j & -j) ret += FT[i][j];
}
return ans;
}
return ret;
}
}