hdu 1556 Color the ball

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思路：线段树成段更新
分析：
1 简单的线段树的成段更新，我们把它看成区间的更改和区间的求和即可，那这样我们只要建立好线段树然后每一次进行更新，最后对每一个[i , i]区间进行求和即可

代码：

#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
using namespace std;

const int MAXN = 100010;
struct Node{
    int left;
    int right;
    int mark;//延时标记
    int sum;
};
Node node[4*MAXN];
int N;

//向上更新
void push_up(int pos){
    node[pos].sum = node[pos<<1].sum + node[(pos<<1)+1].sum;
}

//向下更新i
void push_down(int pos){
    if(node[pos].mark){
       node[pos<<1].mark += node[pos].mark;
       node[(pos<<1)+1].mark += node[pos].mark; 
       node[pos<<1].sum += node[pos].mark*(node[pos<<1].right-node[pos<<1].left+1);
       node[(pos<<1)+1].sum += node[pos].mark*(node[(pos<<1)+1].right-node[(pos<<1)+1].left+1);
       node[pos].mark = 0;
    }
}

//建立线段树
void buildTree(int left , int right , int pos){
    node[pos].left = left;
    node[pos].right = right;
    node[pos].mark = 0;
    if(left == right){
      node[pos].sum = 0;
      return;
    }
    int mid = (left+right)>>1;
    buildTree(left , mid , pos<<1);
    buildTree(mid+1 , right , (pos<<1)+1);
    push_up(pos);
}

//更新
void update(int left , int right , int value , int pos){
    if(left <= node[pos].left && right >= node[pos].right){
       node[pos].mark += value;
       node[pos].sum += value*(node[pos].right-node[pos].left+1);
       return;
    }
    push_down(pos);
    int mid = (node[pos].left + node[pos].right)>>1;
    if(right <= mid)
        update(left , right , value , pos<<1);
    else if(left > mid)
        update(left , right , value , (pos<<1)+1);
    else{
        update(left , mid , value , pos<<1);
        update(mid+1 , right , value , (pos<<1)+1);
    }
    push_up(pos);
}

//查询
int query(int left , int right , int pos){
    if(node[pos].left == left && node[pos].right == right)
      return node[pos].sum;
    int mid = (node[pos].left+node[pos].right)>>1;
    push_down(pos);//继续向下更新，这样才能完全更新完毕
    if(right <= mid)
       return query(left , right , pos<<1);
    else if(left > mid) 
       return query(left , right , (pos<<1)+1);
    else
       return query(left , mid , pos<<1) + query(mid+1 , right , (pos<<1)+1);
}

int main(){
    int x , y;
    while(scanf("%d" , &N) && N){
        buildTree(1 , N , 1);
        int cnt = N;
        while(cnt--){
           scanf("%d%d" , &x , &y);
           update(x , y , 1 , 1);
        }
        for(int i = 1 ; i <= N ; i++){
           if(i == 1) printf("%d" , query(i , i , 1));
           else printf(" %d" , query(i , i , 1));
        }   
        printf("\n");
    }
    return 0;
}