hdoj 5443 The Water Problem【线段树求区间最大值】

题目链接：http://acm.hdu.edu.cn/showproblem.php?pid=5443

刷道水题助助兴

?

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61

#include<stdio.h> #include<string.h> #include<algorithm> #include<stack> #define MAX 2100 #define INF 0x7fffff using namespace std; int n,m; int Max[MAX]; void pushup(int o) {     Max[o]=max(Max[o<<1],Max[o<<1|1]); } void gettree(int o,int l,int r) {     if(l==r)     {         scanf("%d",&Max[o]);         return ;     }     int mid=(l+r)>>1;     gettree(o<<1,l,mid);     gettree(o<<1|1,mid+1,r);     pushup(o); } int find(int o,int l,int r,int L,int R) {     if(L<=l&&R>=r)     {         return Max[o];     }     int ans=0;     int mid=(l+r)>>1;     if(R<=mid)         ans=max(ans,find(o<<1,l,mid,L,R));     else if(L>mid)         ans=max(ans,find(o<<1|1,mid+1,r,L,R));     else     {         ans=max(ans,find(o<<1,l,mid,L,R));         ans=max(ans,find(o<<1|1,mid+1,r,L,R));     }     return ans; } int main() {     int t,i,j,a,b;     scanf("%d",&t);     while(t--)     {         scanf("%d",&n);         gettree(1,1,n);         scanf("%d",&m);         while(m--)         {             scanf("%d%d",&a,&b);             printf("%d\n",find(1,1,n,a,b));         }     }     return 0; }