标签：线段树

I Hate It

Time Limit: 9000/3000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 38359    Accepted Submission(s): 15178

5 6
1 2 3 4 5
Q 1 5
U 3 6
Q 3 4
Q 4 5
U 2 9
Q 1 5

5
6
5
9

Hint
Huge input,the C function scanf() will work better than cin
 

本来看到找最大直接用rmq的，一写发现rmq更新耗时太大了。。。。。用线段树模板稍微改一下就过了，把和改成最大就行

#include<iostream>
#include<cstdio>
#include<cmath>
#include<algorithm>
#define maxn 200001
using namespace std;
const int MX=200001;
int n,t;
int tree[MX*4];
int max1(int a,int b)
{
    return a>b?a:b;
}
void up(int index)
{
    tree[index]=max1(tree[index<<1],tree[index<<1|1]);
}
void create(int index,int l,int r)
{
    if(l==r)
      {
          scanf("%d",&tree[index]);return;
      }
    int mind=(l+r)/2;
    create(index<<1,l,mind);
    create(index<<1|1,mind+1,r);
    up(index);
}
int getse(int index,int s,int e,int l,int r)
{
    if(s<=l&&r<=e)
        return tree[index];
    int ans=0;
    int mind=(r+l)/2;
    if(s<=mind)
        ans=max1(ans,getse(index<<1,s,e,l,mind));
    if(e>mind)
        ans=max1(ans,getse(index<<1|1,s,e,mind+1,r));
    return ans;
}
void update(int index,int p,int v,int l,int r)
{
    if(l==r){
        tree[index]=max1(tree[index],v);return;
    }
    int mind=(r+l)/2;
    if(p<=mind) update(index<<1,p,v,l,mind);
    else update(index<<1|1,p,v,mind+1,r);
    up(index);
}
int main()
{
    while(scanf("%d%d",&n,&t)!=EOF)
    {
    create(1,1,n);
    int a,b;
    char g;
    while(t--)
    {
        getchar();
        scanf("%c%d%d",&g,&a,&b);
        if(g=='Q')
        {
           printf("%d\n", getse(1,a,b,1,n));
        }else{
            update(1,a,b,1,n);
        }
    }
    }
    return 0;
}

HDU1754I Hate It,布布扣,bubuko.com

HDU1754I Hate It

标签：线段树

原文地址：http://blog.csdn.net/fljssj/article/details/38470821