线段树模板

//线段树模板（单点更新）
#define Mid ((l+r)>>1)
#define lson rt<<1,l,Mid
#define rson rt<<1|1,Mid+1,r
const int maxn = 100010;
int sum[maxn<<2];

void build(int rt,int l,int r)
{
if(l==r){
scanf("%d",&sum[rt]);
}else{
build(lson);
build(rson);
sum[rt] = sum[rt<<1] + sum[rt<<1|1];
}
}

void update(int rt,int l,int r,int pos,int num)		//修改pos位值为num
{
if(l == r && r == pos){
sum[rt] += num;
}else{
if( pos <= Mid)
update(lson,pos,num);
else
update(rson,pos,num);
sum[rt] = sum[rt<<1] + sum[rt<<1|1];
}
}

int query(int rt,int l,int r,int L,int R)			//查询[L,R]
{
if(L <= l && r <= R){
return sum[rt];
}else{
int tmp = 0;
if( L <= Mid)
tmp += query(lson,L,R);
if( R > Mid)
tmp += query(rson,L,R);
return tmp;
}
}

int main()
{
int n,L,R;
while(scanf("%d",&n)!=EOF){
build(1,1,n);
scanf("%d%d",&L,&R);
update(1,1,n,L,R);
scanf("%d%d",&L,&R);
printf("%d\n", query(1,1,n,L,R));       //修改L处值为R
}
return 0;
}

//线段树模板（区间更新）
#define Mid ((l+r)>>1)
#define lson rt<<1,l,Mid
#define rson rt<<1|1,Mid+1,r
const int maxn = 100010;
int sum[maxn<<2],add[maxn<<2];

void build(int rt,int l,int r)
{
add[rt] = 0;
if(l == r){
scanf("%d",&sum[rt]);                       //省个数组
}else{
build(lson);
build(rson);
sum[rt]=sum[rt<<1]+sum[rt<<1|1];
}
}

void pushDown(int rt,int len)
{
add[rt<<1] = add[rt<<1|1] = add[rt];
sum[rt<<1] = (len-(len>>1))*add[rt];
sum[rt<<1|1] = (len>>1)*add[rt];
add[rt] = 0;
}

void update(int rt,int l,int r,int L,int R,int z)    //更新[L,R]为z
{
if(L <= l && r <= R){
add[rt] = z;
sum[rt] = (r-l+1)*z;
}else{
if(add[rt])
pushDown(rt,r-l+1);
if(L <= Mid)
update(lson,L,R,z);
if(R > Mid)
update(rson,L,R,z);
sum[rt] = sum[rt<<1] + sum[rt<<1|1];
}
}

int query(int rt,int l,int r,int L,int R)           //查询[L,R]，调用:(1,1,n,L,R)
{
if(L <= l && r <= R){
return sum[rt];
}else{
if(add[rt])
pushDown(rt,r-l+1);
int t = 0;
if(L <= Mid)
t += query(lson,L,R);
if(R > Mid)
t += query(rson,L,R);
return t;
}
}

int main()
{
int L,R,z;
while(scanf("%d%d",&n,&m)!=EOF){
build(1,1,n);
while(m--){
scanf("%*c%c",&op);
if(op=='C'){
scanf("%d%d%d",&L,&R,&z);
update(1,1,n,L,R,z);
}else{
scanf("%d%d",&L,&R);
printf("%d\n",query(1,1,n,L,R));
}
}
}
}