RMQ-區間最大差值(ST表)
阿新 • • 發佈:2018-11-27
#include<iostream> #include<algorithm> using namespace std; int MaxNum[500][50000]; int MinNum[500][50000]; int a[50000]; void ST(int N) { int temp = (int)(log((double)N) / log(2.0)); for (int i = 0; i < N; i++) MaxNum[0][i] = a[i],MinNum[0][i]=a[i]; for (int i = 1; i <= temp; ++i) for (int j = 0; j + (1 << i)-2 <N; ++j) MaxNum[i][j] = max(MaxNum[i - 1][j], MaxNum[i - 1][j + (1 << (i - 1))]), MinNum[i][j] = min(MinNum[i - 1][j], MinNum[i - 1][j + (1 << (i - 1))]) ; } int query(int L, int R) { int k = (int)(log((double)(R - L + 1)) / log(2.0)); return max(MaxNum[k][L], MaxNum[k][R - (1 << k) + 1])-min(MinNum[k][L], MinNum[k][R - (1 << k) + 1]); } int main() { int n,m; cin >> n>>m; for (int i = 0; i < n; ++i)cin >> a[i]; ST(n); while (m--) { int i, j; cin >> i >> j; cout << query(i - 1, j - 1)<<endl; } }