hdu 1754（种一棵线段树）

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感谢小鹏同学的耐心debug。。。。。。发现是少写一个return。。。导致调试好长时间。。。囧。。

#include<iostream>#include<cstdio>#include<cstring>using namespace std;#define N 200005#define LL(x) (x<<1)#define RR(x) (x<<1|1)struct node{    int L,R,val;}edge[N<<2];int buit(int L,int R,int i){    edge[i].L=L,edge[i].R=R;    if(L==R){        scanf("%d",&edge[i].val);        return edge[i].val;    }    int mid=(edge[i].L+edge[i].R)/2;    return edge[i].val=max(buit(mid+1,R,RR(i)),buit(L,mid,LL(i)));}void updata(int id,int x,int i){    if(edge[i].L==edge[i].R){        edge[i].val=x;return;    }    int mid=(edge[i].L+edge[i].R)/2;    if(id<=mid) updata(id,x,LL(i));    else updata(id,x,RR(i));    edge[i].val=max(edge[RR(i)].val,edge[LL(i)].val);}int query(int L,int R,int i){    if(L==edge[i].L && R==edge[i].R) return edge[i].val;    int mid=(edge[i].L+edge[i].R)/2;    if(R<=mid) return query(L,R,LL(i));    else if(L>mid) return query(L,R,RR(i));    else return max(query(mid+1,R,RR(i)),query(L,mid,LL(i)));}int main(){    int n,m,x,y;    char s[5];    while(scanf("%d%d",&n,&m)!=-1){        buit(1,n,1);        while(m--){            scanf("%s%d%d",s,&x,&y);            if(s[0]=='Q') printf("%d\n",query(x,y,1));            else updata(x,y,1);        }    }}