hdu1166(线段树模版，区间求和）

http://acm.hdu.edu.cn/showproblem.php?pid=1166

用线段树做，比树状数组费时

#include<iostream>

using namespace std;

const int N=50005;

struct 

{

    int left,right,num;

}s[4*N];

int data[N];

void build(int left,int right,int n)

{

    int mid;

    mid=(left+right)/2;

    if(left==right)

    {

        s[n].left=left;

        s[n].right=right;

        s[n].num=data[left];

    }

    else

    {

        s[n].left=left;

        s[n].right=right;

        build(left,mid,n*2);

        build(mid+1,right,n*2+1);

        s[n].num=s[n*2].num+s[n*2+1].num;

    }

}

int sum(int left,int right,int n)

{

    int mid=(s[n].left+s[n].right)/2;

    if(s[n].left==left&&s[n].right==right)

    {

        return s[n].num;

    }

    else

        if(left>mid)

            sum(left,right,n*2+1);

        else

            if(right<=mid)

                sum(left,right,n*2);

            else

                return (sum(left,mid,n*2)+sum(mid+1,right,n*2+1));

}

void add(int i,int j,int n)

{

    int mid=(s[n].left+s[n].right)/2;

    if(s[n].left==i&&s[n].right==i)

    {

        s[n].num+=j;

        int count=n/2;

        while(count>=1)

        {

            s[count].num+=j;

            count/=2;

        }

    }

    else

        if(i>mid)

            add(i,j,n*2+1);

        else

            if(i<=mid)

                add(i,j,n*2);

}

int main()

{

    int t,f=0;

    scanf("%d",&t);

    while(t--)

    {

        int n;

        scanf("%d",&n);

        for(int i=1;i<=n;i++)

            scanf("%d",&data[i]);

        build(1,n,1);

        getchar();

        printf("Case %d:\n",++f);

        char s[10];

        scanf("%s",s);

        while(1)

        {

            if(s[0]=='Q')

            {

                int x,y;

                scanf("%d%d",&x,&y);

                printf("%d\n",sum(x,y,1));

            }

            else

                if(s[0]=='A')

                {

                    int x,y;

                    scanf("%d%d",&x,&y);

                    add(x,y,1);

                }

                else

                    if(s[0]=='S')

                    {

                        int x,y;

                        scanf("%d%d",&x,&y);

                        add(x,-y,1);

                    }

                    else

                        if(s[0]=='E')

                            break;

                        getchar();

                        scanf("%s",s);

        }

    }

    return 0;

}