【POJ】3264 Balanced Lineup 
 1 #include<cstdio>
 2 #define MAXN 50010
 3 #define INF 987654321
 4 int a[MAXN<<2],b[MAXN<<2];
 5 inline int MAX(int x,int y)
 6 {
 7     return x>y?x:y;
 8 }
 9 inline int MIN(int x,int y)
10 {
11     return x>y?y:x;
12 }
13 inline void PushUp(int rt)
14 {
15     a[rt]=MAX(a[rt<<1],a[rt<<1|1]);
16     b[rt]=MIN(b[rt<<1],b[rt<<1|1]);
17 }
18 void Build(int L,int R,int rt)
19 {
20     if(L==R)
21     {
22         scanf("%d",&a[rt]);
23         b[rt]=a[rt];
24     }
25     else
26     {
27         int mid=(L+R)>>1;
28         Build(L,mid,rt<<1);
29         Build(mid+1,R,rt<<1|1);
30         PushUp(rt);
31     }
32 }
33 int Big(int x,int y,int L,int R,int rt)
34 {
35     if(x<=L&&R<=y)
36         return a[rt];
37     int mid,ans;
38     mid=(L+R)>>1;
39     ans=-INF;
40     if(mid>=x)
41         ans=MAX(ans,Big(x,y,L,mid,rt<<1));
42     if(y>mid)
43         ans=MAX(ans,Big(x,y,mid+1,R,rt<<1|1));
44     return ans;
45 }
46 int Small(int x,int y,int L,int R,int rt)
47 {
48     if(x<=L&&R<=y)
49         return b[rt];
50     int mid,ans;
51     mid=(L+R)>>1;
52     ans=INF;
53     if(mid>=x)
54         ans=MIN(ans,Small(x,y,L,mid,rt<<1));
55     if(y>mid)
56         ans=MIN(ans,Small(x,y,mid+1,R,rt<<1|1));
57     return ans;
58 }
59 int main()
60 {
61     int n,q,x,y;
62     while(~scanf("%d%d",&n,&q))
63     {
64         Build(1,n,1);
65         while(q--)
66         {
67             scanf("%d%d",&x,&y);
68             printf("%d\n",Big(x,y,1,n,1)-Small(x,y,1,n,1));
69         }
70     }
71     return 0;
72 }
posted on 2012-05-21 16:32  DrunBee  阅读(281)  评论(0)  编辑  收藏  举报