九度oj 1544 数字序列区间最小值

原题链接：http://ac.jobdu.com/problem.php?pid=1544

RMQ线段树。。。

如下：

 1 #include<algorithm>

 2 #include<iostream>

 3 #include<cstdlib>

 4 #include<cstring>

 5 #include<cstdio>

 6 using std::min;

 7 const int Max_N = 101000;

 8 const int INF = 0x7fffffff;

 9 struct SegTree{

10     struct Node{

11         int v;

12     }seg[Max_N << 2];

13     void init(int n){

14         built(1, 1, n);

15     }

16     inline void built(int root, int l, int r){

17         if (l == r){

18             scanf("%d", &seg[root].v);

19             return;

20         }

21         int mid = (l + r) >> 1;

22         built(root << 1, l, mid);

23         built(root << 1 | 1, mid + 1, r);

24         seg[root].v = min(seg[root << 1].v, seg[root << 1 | 1].v);

25     }

26     inline int query(int root, int l, int r, int x, int y){

27         if (x > r || y < l) return INF;

28         if (x <= l && y >= r){

29             return seg[root].v;

30         }

31         int mid = (l + r) >> 1;

32         int v1 = query(root << 1, l, mid, x, y);

33         int v2 = query(root << 1 | 1, mid + 1, r, x, y);

34         return min(v1, v2);

35     }

36     inline void gogo(int n){

37         int m, a, b;

38         scanf("%d", &m);

39         while (m--){

40             scanf("%d %d", &a, &b);

41             printf("%d\n", query(1, 1, n, a, b));

42         }

43     }

44 }sg;

45 int main(){

46 #ifdef LOCAL

47     freopen("in.txt", "r", stdin);

48     freopen("out.txt", "w+", stdout);

49 #endif

50     int n;

51     while (~scanf("%d", &n)){

52         sg.init(n), sg.gogo(n);

53     }

54     return 0;

55 }

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