hdu1754-I Hate It(线段树）

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#include<iostream>#include<cstring>#include<cstdio>#include<cmath>#include<algorithm>#include<cstdlib>#include<map>#include<queue>#include <deque>#include <list>#include <ctime>#include <stack>#include <vector>#include<set>const int Maxn =200003;#define MODtypedef long long ll;#define FOR(i,j,n) for(int i=j;i<=n;i++)#define DFR(i,j,k) for(int i=j;i>=k;--i)#define lowbit(a) a&-a#define lson l,m,rt<<1#define rson m+1,r,rt<<1|1const int inf = 0x3f3f3f3f;const double pi = acos(-1.0);int MAX[Maxn<<2];using namespace std;int max(int a,int b){return a>b?a:b;}void PushUP(int rt){ MAX[rt]=Max(MAX[rt<<1],MAX[rt<<1|1]);}void build(int l,int r,int rt){   if(l==r){scanf("%d",&MAX[rt]);return;}    int m=(l+r)>>1;    build(lson);    build(rson);    PushUP(rt);}void update(int p,int sc,int l,int r,int rt){ if(l==r){MAX[rt]=sc;return;}  int m=(l+r)>>1;  if(p<=m)update(p,sc,lson);  else update(p,sc,rson);  PushUP(rt);}int query(int L,int R,int l,int r,int rt){   if(L<=l&&r<=R)return MAX[rt];    int m=(l+r)>>1;    int ret=0;    if(L<=m)ret=Max(ret,query(L,R,lson));    if(R>m)ret=Max(ret,query(L,R,rson));    return ret;}int main(){   int n,m;    while(~scanf("%d%d",&n,&m))    {   build(1,n,1);        while(m--)            {char op[2];             int a,b;             scanf("%s%d%d",op,&a,&b);            if(op[0]=='Q')printf("%d\n",query(a,b,1,n,1));            else update(a,b,1,n,1);            }    }    return 0;}
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