RMQ-ST求区间最值

二分果然是宇宙最强法则。。。

 

 1 #include <iostream>

 2 #include <algorithm>

 3 #include <cstring>

 4 #include <string>

 5 #include <cstdio>

 6 #include <cmath>

 7 #define MAXN 2222222

 8 #define MAXM 11111

 9 #define lch(x) x<<1

10 #define rch(x) x<<1|1

11 #define lson l,m,rt<<1

12 #define rson m+1,r,rt<<1|1

13 using namespace std;

14 int mi[MAXN][22], mx[MAXN][22], w[MAXN];

15 int n, q;

16 void rmqinit()

17 {

18     for(int i = 1; i <= n; i++) mi[i][0] = mx[i][0] = w[i];

19     int m = (int)(log(n * 1.0) / log(2.0));

20     for(int i = 1; i <= m; i++)

21         for(int j = 1; j <= n; j++)

22         {

23             mx[j][i] = mx[j][i - 1];

24             if(j + (1 << (i - 1)) <= n) mx[j][i] = max(mx[j][i], mx[j + (1 << (i - 1))][i - 1]);

25             mi[j][i] = mi[j][i - 1];

26             if(j + (1 << (i - 1)) <= n) mi[j][i] = min(mi[j][i], mi[j + (1 << (i - 1))][i - 1]);

27         }

28 }

29 int rmqmin(int l,int r)

30 {

31     int m = (int)(log((r - l + 1) * 1.0) / log(2.0));

32     return min(mi[l][m] , mi[r - (1 << m) + 1][m]);

33 }

34 int rmqmax(int l,int r)

35 {

36     int m = (int)(log((r - l + 1) * 1.0) / log(2.0));

37     return max(mx[l][m] , mx[r - (1 << m) + 1][m]);

38 }

39 int main()

40 {

41     scanf("%d", &n);

42     for(int i = 1; i <= n; i++) scanf("%d", &w[i]);

43     rmqinit();

44     int l, r;

45     scanf("%d",&q);

46     while(q--)

47     {

48         scanf("%d%d", &l, &r);

49         printf("%d\n", rmqmin(l, r));

50     }

51     return 0;

52 }

代码君