hdu1754

来源：互联网发布：淘宝客如何找商家编辑：程序博客网时间：2024/06/08 01:32

http://acm.hdu.edu.cn/showproblem.php?pid=1754

#include<iostream>#include<cstdio>#include<cstring>#define N 200000using namespace std;struct node{int l,r,max;int mid(){return (l+r)>>1;}};node tree[N*3];void buildtree(int l,int r,int pos){tree[pos].l=l;tree[pos].r=r;if(l==r){scanf("%d",&tree[pos].max);return ;}buildtree(l,tree[pos].mid(),pos<<1);buildtree(tree[pos].mid()+1,r,(pos<<1)+1);tree[pos].max=tree[pos*2].max;if(tree[pos*2+1].max>tree[pos].max)tree[pos].max=tree[pos*2+1].max;}inline int max1(int a,int b){return a>b?a:b;}int query(int l,int r,int pos){if(tree[pos].l==l&&tree[pos].r==r){return tree[pos].max;}else if(r<=tree[pos].mid()){return query(l,r,pos<<1);}else if(l>=tree[pos].mid()+1){return query(l,r,(pos<<1)+1);}else{return max1(query(l,tree[pos].mid(),pos<<1),query(tree[pos].mid()+1,r,(pos<<1)+1));}}void update(int k,int data,int pos){if(tree[pos].l<=k&&tree[pos].r>=k){tree[pos].max=max1(data,tree[pos].max);if(tree[pos].l==k&&tree[pos].r==k){tree[pos].max=data;return ;}update(k,data,pos<<1);update(k,data,(pos<<1)+1);}return ;}int main(){int n,m;while(scanf("%d%d",&n,&m)!=EOF){buildtree(1,n,1);int i;for(i=0;i<m;i++){char c[2];int t1,t2;scanf("%s%d%d",c,&t1,&t2);if(c[0]=='Q'){printf("%d\n",query(t1,t2,1));}else if(c[0]=='U'){update(t1,t2,1);}}}return 0;}