20 lines
539 B
C++
20 lines
539 B
C++
template< typename T > class sparse_table {
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private: vector<T> st[20];
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public:
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int log(int x) { return 32 - __builtin_clz(x) - 1; }
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sparse_table(vector<T> &A) {
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int N = A.size();
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for (int i = 0; i <= log(N); i++) st[i].resize(N);
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for (int i = 0; i < N; i++) st[0][i] = A[i];
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for (int i = 1; i <= log(N); i++) {
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for (int j = 0; j + (1 << i) < N; j++) st[i][j] = min(st[i - 1][j], st[i - 1][j + (1 << (i - 1))]);
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}
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}
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T query(int i, int j) {
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int k = log(j - i + 1);
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return min(st[k][i], st[k][j - (1 << k) + 1]);
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}
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};
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