线段树模板

struct node{    ll l,r,mid,val,mark;}tree[M<<2];ll s[M];void build(ll left,ll right,ll i)//建树{    tree[i].l=left;tree[i].r=right;    tree[i].mid=(left+right)>>1;tree[i].mark=0;    if(left==right){tree[i].val=s[left]; return;}    build(left,tree[i].mid,i*2);    build(tree[i].mid+1,right,i*2+1);    tree[i].val=tree[i*2].val+tree[i*2+1].val;}void update(int pos,ll val,int i)//点更新{    tree[i].val+=val;    if(tree[i].l==tree[i].r)return;    if(pos<=tree[i].mid)update(pos,val,i*2);    else update(pos,val,i*2+1);}ll query(int left,int right,int i)//点查询{    if(tree[i].l==left&&tree[i].r==right)return tree[i].val;    if(right<=tree[i].mid)query(left,right,i*2);    else if(left>tree[i].mid)query(left,right,i*2+1);    else return query(left,tree[i].mid,i*2)+query(tree[i].mid+1,right,i*2+1);}void update(int left,int right,ll val,int i)//区间更新{    if(tree[i].l==left&&tree[i].r==right){tree[i].mark+=val;return;}    tree[i].val+=val*(right-left+1);    if(tree[i].mid<left)update(left,right,val,2*i+1);    else if(tree[i].mid>=right)update(left,right,val,2*i);    else    {        update(left,tree[i].mid,val,2*i);        update(tree[i].mid+1,right,val,2*i+1);    }}ll query(int left,int right,int i)//区间查询{    if(tree[i].l==left&&tree[i].r==right)  return tree[i].val+tree[i].mark*(right-left+1);    if(tree[i].mark!=0)    {        tree[i*2].mark+=tree[i].mark;tree[i*2+1].mark+=tree[i].mark;        tree[i].val+=(tree[i].r-tree[i].l+1)*tree[i].mark;tree[i].mark=0;    }    if(tree[i].mid>=right){return query(left,right,i*2);}    else if(tree[i].mid<left){return query(left,right,i*2+1);}    else{return query(left,tree[i].mid,i*2)+query(tree[i].mid+1,right,i*2+1);}}int main(){    int n,m;    while(scanf("%d%d",&n,&m)!=EOF)    {        for(int i=1;i<=n;i++)            scanf("%I64d",&s[i]);        build(0,M,1);        ......    }    return 0;}