hdu 1166 敌兵布阵 【线段树】

好好学一下线段树----

从0开始----加油～

单点更新的

 #include<cstdio>
 #include<cstring>
 #include<iostream>
 #include<algorithm>
 #include<cmath>
 #include<vector>
 using namespace std;
 #define lp (p << 1)
 #define rp (p << 1 | 1)
 #define getmid(l,r) (l + (r - l) / 2)

 const int maxn = ;
 struct node{
     int l,r,s;
 }t[*maxn];

 int a[maxn],n;

 int calc(int a,int b) { return a+b; }

 void Push_up(int p){
     t[p].s = calc(t[lp].s,t[rp].s);
 }

 void Build_tree(int p,int l,int r){
     t[p].l = l;
     t[p].r = r;
     if(l == r){ t[p].s = a[l];return;}
     int mid = getmid(l,r);
     Build_tree(lp,l,mid);
     Build_tree(rp,mid+,r);
     Push_up(p);
 }

 void update(int p,int s,int w){//给s点加上w
     if(t[p].l == t[p].r) {
         t[p].s += w;
         return;
     }
     int mid = getmid(t[p].l,t[p].r);
     if(s <= mid) update(lp,s,w);
     else update(rp,s,w);
     Push_up(p);
 }

 int sum(int p,int l,int r){
     if(t[p].l == l && t[p].r == r) return t[p].s;

         int mid = getmid(t[p].l,t[p].r);
         if(r <= mid) return sum(lp,l,r);
         else if(mid < l) return sum(rp,l,r);
          else return calc(sum(lp,l,mid),sum(rp,mid+,r));
 }

 int main(){
     int T;
     scanf("%d",&T);
     int kase = ;
     while(T--){
         scanf("%d",&n);
         for(int i = ;i <= n;i++) scanf("%d",&a[i]);
         Build_tree(,,n);

     //    for(int i = 1;i <= n;i++)
     //    printf("t[%d].l = %d  t[%d].r = %d  t[%d].s = %d\n",i,t[i].l,i,t[i].r,i,t[i].s);

         char cmd[];
         int x,y;
         printf("Case %d:\n",++kase);
         while(cin >> cmd){
             if(cmd[] == 'E') break;
             else if(cmd[] == 'A'){
             scanf("%d %d",&x,&y);
             update(,x,y);
             }
             else if(cmd[] == 'S'){
             scanf("%d %d",&x,&y);
             update(,x,-y);
             }
             else{
                 scanf("%d %d",&x,&y);
                 printf("%d\n",sum(,x,y));
             }
         }
     }
     return ;
 }