hdu1754I Hate It

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

题意：中文题。

分析：线段树练习题。单点更新，区间查询最大值。（那些跑得快的应该是写的zkw线段树吧。）

代码：

#include<map>#include<set>#include<cmath>#include<queue>#include<bitset>#include<math.h>#include<cstdio>#include<vector>#include<string>#include<cstring>#include<iostream>#include<algorithm>#pragma comment(linker, "/STACK:102400000,102400000")using namespace std;const int N=200100;const int MAX=1000000100;const int mod=100000000;const int MOD1=1000000007;const int MOD2=1000000009;const double EPS=0.00000001;typedef long long ll;const ll MOD=998244353;const ll INF=10000000010;typedef double db;typedef unsigned long long ull;char s[3];int a[N],mx[4*N];void build(int x,int l,int r) {    if (l==r) { mx[x]=a[l];return ; }    int mid=(l+r)>>1;    build(2*x,l,mid);    build(2*x+1,mid+1,r);    mx[x]=max(mx[2*x],mx[2*x+1]);}int query(int x,int l,int r,int L,int R) {    if (l==L&&r==R) return mx[x];    int mid=(l+r)>>1;    if (R<=mid) return query(2*x,l,mid,L,R);    else if (L>mid) return query(2*x+1,mid+1,r,L,R);        else return max(query(2*x,l,mid,L,mid),query(2*x+1,mid+1,r,mid+1,R));}void updata(int x,int l,int r,int y,int z) {    if (l==r) { mx[x]=z;return ; }    int mid=(l+r)>>1;    if (y<=mid) updata(2*x,l,mid,y,z);    else updata(2*x+1,mid+1,r,y,z);    mx[x]=max(mx[2*x],mx[2*x+1]);}int main(){    int i,n,m,l,r;    while (scanf("%d%d", &n, &m)!=EOF) {        for (i=1;i<=n;i++) scanf("%d", &a[i]);        build(1,1,n);        while (m--) {            scanf("%s%d%d", s, &l, &r);            if (s[0]=='Q') printf("%d\n", query(1,1,n,l,r));            else updata(1,1,n,l,r);        }    }    return 0;}

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