HDU 1754 I Hate It

I Hate It

Time Limit: 9000/3000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 28977    Accepted Submission(s): 11496

Problem Description

很多学校流行一种比较的习惯。老师们很喜欢询问，从某某到某某当中，分数最高的是多少。
这让很多学生很反感。

不管你喜不喜欢，现在需要你做的是，就是按照老师的要求，写一个程序，模拟老师的询问。当然，老师有时候需要更新某位同学的成绩。

 

Input

本题目包含多组测试，请处理到文件结束。
在每个测试的第一行，有两个正整数 N 和 M ( 0<N<=200000,0<M<5000 )，分别代表学生的数目和操作的数目。
学生ID编号分别从1编到N。
第二行包含N个整数，代表这N个学生的初始成绩，其中第i个数代表ID为i的学生的成绩。
接下来有M行。每一行有一个字符 C (只取'Q'或'U') ，和两个正整数A，B。
当C为'Q'的时候，表示这是一条询问操作，它询问ID从A到B(包括A,B)的学生当中，成绩最高的是多少。
当C为'U'的时候，表示这是一条更新操作，要求把ID为A的学生的成绩更改为B。

 

Output

对于每一次询问操作，在一行里面输出最高成绩。

 

Sample Input

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

 

Sample Output

5

6

5

9

Hint

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

 

Author

linle

 

Source

2007省赛集训队练习赛（6）_linle专场

 

Recommend

lcy

 

思路：线段树

 

超空间代码：

#include <iostream>
#include <cstdlib>
#include <cstring>
#include <cstdio>
#include <algorithm>
using namespace std;
int n,m;
char str;
int a,b;
int flag;
int ans;
struct Node
{
    int ld,rd;
    Node *lc,*rc;
    int maxn;
};
int map[200010];
Node *buildtree(int begin,int end)
{
    Node* p = new Node;
    p -> ld = begin;
    p -> rd = end;
    int maxn = 0;
    for(int i = begin;i <= end;i ++)
      if(map[i] > maxn)
         maxn = map[i];
    p -> maxn = maxn;
    if(begin == end)
      return p;
    p -> lc = buildtree(begin,(begin + end) / 2);
    p -> rc = buildtree((begin + end) / 2 + 1,end);
    return p;
}
void insert(Node* T,int position,int score)
{
    if(ans == 1)
        return ;
    if(position >= T -> ld && position <= T -> rd)
    {
        if(score > T -> maxn)
            T -> maxn = score;
        if(T -> ld == T -> rd)
        {
            ans = 1;
            return ;
        }
    }
    if(T -> ld == T -> rd == position)
    {
        ans = 1;
        return ;
    }
    if(ans == 1)
        return ;
    if(position <= (T -> ld + T -> rd) / 2)
        insert(T -> lc,position,score);
    if(position > (T -> ld + T -> rd) / 2)
        insert(T -> rc,position,score);
}
int search(Node* T,int begin,int end)
{
    if(begin <= T -> ld && end >= T -> rd)
    {
        if(T -> maxn > flag)
           flag = T -> maxn;
        return flag;
    }
    if(begin <= (T -> ld + T -> rd) / 2)
        search(T -> lc,begin,end);
    if(end > (T -> ld + T -> rd) / 2)
        search(T -> rc,begin,end);
    return flag;
}
int main()
{
    while(~scanf("%d%d",&n,&m))
    {
        memset(map,0,sizeof(map));
        for(int i = 1;i <= n;i ++)
           scanf("%d",&map[i]);
        Node* root = buildtree(1,n);
        for(int i = 1;i <= m;i ++)
        {
            scanf(" %c%d%d",&str,&a,&b);
            if(str == 'U')
               insert(root,a,b);
            else
            {
                flag = 0;ans = 0;
                printf("%d
",search(root,a,b));
            }
        }
    }
    return 0;
}

AC代码：

#include <iostream>
#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <algorithm>
#include <cmath>
using namespace std;
#define MAXN 1100024
int n,m;
int map[MAXN];
int a,b;
char str_char;
int ans;
struct Node
{
    int leftboundary,rightboundary;
    int max;
}Tree[MAXN];
int buildtree(int position,int begin,int end)
{
    Tree[position].leftboundary = begin;
    Tree[position].rightboundary = end;
    if(begin == end)
       return Tree[position].max = map[begin];
    int x = buildtree(2 * position,begin,(begin + end) / 2);
    int y = buildtree(2 * position + 1,(begin + end) / 2 + 1,end);
    return Tree[position].max = x > y ? x : y;
}
void insert(int position,int begin,int score)
{
    if(begin >= Tree[position].leftboundary && begin <= Tree[position].rightboundary)
    {
        if(Tree[position].max < score)
             Tree[position].max = score;
    }
    if(Tree[position].leftboundary == Tree[position].rightboundary)
         return ;
    if(begin <= (Tree[position].leftboundary + Tree[position].rightboundary) / 2)
       insert(2 * position,begin,score);
    if(begin > (Tree[position].leftboundary + Tree[position].rightboundary) / 2)
       insert(2 * position + 1,begin,score);
}
int search(int position,int begin,int end)
{
    if(Tree[position].leftboundary == begin && end == Tree[position].rightboundary)
    {
        return Tree[position].max;
    }
    int mid = (Tree[position].leftboundary + Tree[position].rightboundary) / 2;
    if(end <= (Tree[position].leftboundary + Tree[position].rightboundary) / 2)
         return search(2 * position,begin,end);
    else
    if(begin > (Tree[position].leftboundary + Tree[position].rightboundary) / 2)
    {
        return search(2 * position + 1,begin,end);
    }
    else
    {
        int x = search(2 * position,begin,mid);
        int y = search(2 * position + 1,mid + 1,end);
        return x > y ? x : y;
    }
}
int main()
{
    while(~scanf("%d%d",&n,&m))
    {
        memset(map,0,sizeof(map));
        memset(Tree,0,sizeof(Tree));
        for(int i = 1;i <= n;i ++)
        {
            scanf("%d",&map[i]);
        }
        buildtree(1,1,n);
        ans = 0;
        while(m --)
        {
            scanf(" %c%d%d",&str_char,&a,&b);
            if(str_char == 'U')
            {
                insert(1,a,b);
                map[a] = b;
            }
            if(str_char == 'Q')
            {
                printf("%d
",search(1,a,b));
            }
        }
    }
    return 0;
}

修改后仍然超空间代码：

#include <iostream>
#include <cstdlib>
#include <cstring>
#include <cstdio>
#include <algorithm>
using namespace std;
int n,m;
char str;
int a,b;
int flag;
int ans;
struct Node
{
    int ld,rd;
    Node *lc,*rc;
    int maxn;
};
int map[200001];
Node *buildtree(int begin,int end)
{
    Node* p = new Node;
    p -> ld = begin;
    p -> rd = end;
    if(begin == end)
    {
        p -> maxn = map[begin];
        return p;
    }
    p -> lc = buildtree(begin,(begin + end) / 2);
    p -> rc = buildtree((begin + end) / 2 + 1,end);
    int x = p -> lc -> maxn;int y = p -> rc -> maxn;
    p -> maxn = x > y ? x : y;
    return p;
}
void insert(Node* T,int position,int score)
{
    if(T -> ld <= position && T -> rd >= position)
    {
        if(T -> maxn < score)
            T -> maxn = score;
    }
    if(T -> ld == T -> rd)
        return ;
    if(position <= (T -> ld + T -> rd) / 2)
        insert(T -> lc,position,score);
    if(position > (T -> ld + T -> rd) / 2)
        insert(T -> rc,position,score);
}
int search(Node* T,int begin,int end)
{
    if(T -> ld == begin && T -> rd == end)
    {
        return T -> maxn;
    }
    int mid = (T -> ld + T -> rd) / 2;
    if(end <= mid)
    {
        return search(T -> lc,begin,end);
    }
    else
    if(begin > mid)
    {
        return search(T -> rc,begin,end);
    }
    else
    {
        int x = search(T -> lc,begin,mid);
        int y = search(T -> rc,mid + 1,end);
        return x > y ? x : y;
    }
}
int main()
{
    while(~scanf("%d%d",&n,&m))
    {
        memset(map,0,sizeof(map));
        for(int i = 1;i <= n;i ++)
           scanf("%d",&map[i]);
        Node* root = buildtree(1,n);
        for(int i = 1;i <= m;i ++)
        {
            scanf(" %c%d%d",&str,&a,&b);
            if(str == 'U')
            {
               insert(root,a,b);
               map[a] = b;
            }
            else
            {
                flag = 0;ans = 0;
                printf("%d
",search(root,a,b));
            }
        }
    }
    return 0;
}

代码：哈囧