hdu1166 敌兵布阵，线段树

最近开始学习线段树，前天开始的时候看完了百度百科上的线段树介绍，上网搜了许多题目，结果第一次写线段树，居然是二维。。。果断不可做。。。写了四个小时发现思路不对。。。

于是，听说胡浩有一篇线段树的博客很经典，就开始按照博客开始做题了。。。

这是我ac的第一道线段树题目

#include<stdio.h>#include<stdlib.h>#include<string.h>#include<math.h>#define INF 200000000struct node{    int u;    int v;    int cover;    int left;    int right;}tree[100001];int num[50005],aa,bb,person,tot;void build(int a,int b){    int i,j,k,l,mid;    tot++;    l=tot;    tree[l].u=a;    tree[l].v=b;    tree[l].cover=0;    if(b-a>0)    {        mid=(a+b)/2;        tree[l].left=tot+1;        build(a,mid);        tree[l].right=tot+1;        build(mid+1,b);    }}void insert(int a){    int mid;    if(aa>=tree[a].u&&aa<=tree[a].v)        tree[a].cover+=bb;;    if(tree[a].v-tree[a].u>0)    {        mid=(tree[a].u+tree[a].v)/2;        if(aa<=mid)            insert(tree[a].left);        else            insert(tree[a].right);    }}void delete(int a){    int mid;    if(aa>=tree[a].u&&aa<=tree[a].v)        tree[a].cover-=bb;    if(tree[a].v-tree[a].u>0)    {        mid=(tree[a].v+tree[a].u)/2;        if(aa<=mid)            delete(tree[a].left);        else            delete(tree[a].right);    }}void search(int a){    int mid;    if(tree[a].u>=aa&&tree[a].v<=bb)        person+=tree[a].cover;    else    {        if(tree[a].v-tree[a].u>0)        {            mid=(tree[a].u+tree[a].v)/2;            if(bb<=mid)                search(tree[a].left);            else if(aa>mid)                search(tree[a].right);            else            {                search(tree[a].left);                search(tree[a].right);            }        }    }}int main(){    int n,i,j,k,l,a,b,t;    char s[15];    while(scanf("%d",&t)!=EOF)    {        for(i=1;i<=t;i++)        {            printf("Case %d:\n",i);            scanf("%d",&n);            for(j=1;j<=n;j++)            {                scanf("%d",&num[j]);            }            tot=0;            build(1,n);            for(j=1;j<=n;j++)            {                aa=j;                bb=num[j];                insert(1);            }            while(scanf("%s",&s))            {                if(strcmp(s,"End")==0)                    break;                scanf("%d%d",&aa,&bb);                if(s[0]=='A')                {                    insert(1);                }                else if(s[0]=='S')                {                    delete(1);                }                else if(s[0]='Q')                {                    person=0;                    search(1);                    printf("%d\n",person);                }            }        }    }    return 0;}