hdu 1166 敌兵布阵（线段树入门题）

#include<cstring>
#include<cstdio>

#define M 50005
#define lson l,m,rt<<1
#define rson m+1,r,rt<<1|1

int sum[M<<2];

void PushPlus(int rt){
sum[rt] = sum[rt<<1]+sum[rt<<1|1];
}

void Build(int l,int r,int rt){
if(l == r){
scanf("%d",&sum[rt]);
return ;
}
int m = ( l + r )>>1;

Build(lson);
Build(rson);
PushPlus(rt);
}

void Updata(int p,int add,int l,int r,int rt){

if( l == r ){
sum[rt]+=add;
return ;
}
int m = ( l + r ) >> 1;
if(p<=m)
Updata(p,add,lson);
else
Updata(p,add,rson);

PushPlus(rt);

}

int Query(int L,int R,int l,int r,int rt){

if( L <= l && r <= R ){
return sum[rt];
}
int m = ( l + r ) >> 1;
int ans=0;
if(L<=m )
ans+=Query(L,R,lson);
if(R>m)
ans+=Query(L,R,rson);

return ans;
}
int main(){

int T,n,p;
scanf("%d",&T);
for( p=1 ; p<=T ; p++ ){
printf("Case %d:\n",p);
scanf("%d",&n);
Build(1,n,1);

char op[10];

while( scanf("%s",op) ){
if(op[0]=='E')
break;
int a,b;
scanf("%d %d",&a,&b);
if(op[0] == 'Q')
printf("%d\n",Query(a,b,1,n,1));
else if(op[0] == 'S')
Updata(a,-b,1,n,1);
else
Updata(a,b,1,n,1);

}

}
return 0;
}