82 lines
1.8 KiB
C++
82 lines
1.8 KiB
C++
// Forest Queries
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#include<bits/stdc++.h>
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using namespace std;
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vector<int> get_1D_seg_tree(string row) {
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int n = row.size();
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vector<int> output(2 * n);
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for (int i{}; i < n; i++) {
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output[i + n] = (row[i] == '*');
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}
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for (int i = n - 1; i >= 1; i--) {
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output[i] = output[2 * i] + output[2 * i + 1];
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}
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return output;
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}
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vector<int> merge_2_seg_trees(vector<int> &first, vector<int> &second) {
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vector<int> output(second.size());
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for (int i{}; i < second.size(); i++) {
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output[i] = first[i] + second[i];
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}
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return output;
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}
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int query_1D(vector<int> &seg1D, int n, int x1, int x2) {
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x1 += n;
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x2 += n;
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int s = 0;
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while (x1 <= x2) {
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if (x1 % 2 == 1) {
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s += seg1D[x1];
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x1++;
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}
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if (x2 % 2 == 0) {
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s += seg1D[x2];
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x2--;
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}
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x1 /= 2;
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x2 /= 2;
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}
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return s;
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}
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int query(vector<vector<int>> &seg, int n, int y1, int x1, int y2, int x2) {
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y1 += n; y2 += n;
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int s = 0;
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while (y1 <= y2) {
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if (y1 % 2 == 1) {
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s += query_1D(seg[y1], n, x1, x2);
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y1++;
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}
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if (y2 % 2 == 0) {
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s += query_1D(seg[y2], n, x1, x2);
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y2--;
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}
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y2 /= 2;
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y1 /= 2;
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}
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return s;
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}
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int main() {
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int n, q;
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cin >> n >> q;
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vector<vector<int>> TwoDSeg(2 * n);
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for (int i{}; i < n; i++) {
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string in; cin >> in;
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TwoDSeg[i + n] = get_1D_seg_tree(in);
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}
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for (int i = n - 1; i >= 1; i--) {
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TwoDSeg[i] = merge_2_seg_trees(TwoDSeg[2 * i], TwoDSeg[2 * i + 1]);
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}
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for (int i{}; i < q; i++) {
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int y1, x1, y2, x2; cin >> y1 >> x1 >> y2 >> x2;
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y1--; x1--; y2--; x2--;
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cout << query(TwoDSeg, n, y1, x1, y2, x2) << endl;
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}
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return 0;
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}
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