wikioi1082 线段树和lazy思想

</pre>最原始的lazy思想，注意在update的时候lazy只会更新到所在区间，往下就不会更新了，所以在查询的时候要pushdown更新下端区间。<pre name="code" class="cpp">#include <iostream>#include <cstdio>#include <cstring>#include <algorithm>#include <cmath>#define lson l , m , rt<<1#define rson m+1 , r , rt<<1|1using namespace std;#define maxn 900000int n;long long sum[maxn],lazy[maxn];void pushup(int rt){    sum[rt]=sum[rt<<1]+sum[rt<<1|1];}void pushdown(int rt,int num){    if(lazy[rt])    {        lazy[rt<<1]+=lazy[rt];        lazy[rt<<1|1]+=lazy[rt];        sum[rt<<1]+=(num-(num>>1))*lazy[rt];//左区间多一个        sum[rt<<1|1]+=(num>>1)*lazy[rt];        lazy[rt]=0;    }}void build(int l,int r,int rt){    lazy[rt]=0;    int m=(l+r)>>1;    if(l==r)    {        scanf("%lld",&sum[rt]);        return ;    }    build(lson);    build(rson);    pushup(rt);    return ;}void update(int l,int r,int rt,int x,int y,long long add)//更新函数{    if(x<=l &&r<=y)    {        lazy[rt]+=add;        sum[rt]+=add*(r-l+1);        return;    }    int m=(l+r)>>1;    pushdown(rt,(r-l+1));    if(x<=m)        update(lson,x,y,add);    if(y>m)        update(rson,x,y,add);    pushup(rt);    return;}long long query(int l,int r,int rt,int x,int y)//查询函数{    long long tmp=0;    int m=(l+r)>>1;    if(x<=l &&r<=y)    {        return sum[rt];    }    pushdown(rt,(r-l+1));    if(x<=m)        tmp+=query(lson,x,y);    if(y>m)        tmp+=query(rson,x,y);    return tmp;}int main(){    char a;    int n,q;    int x,y;    long long z;    while(scanf("%d",&n)!=EOF)    {        int b,c;        long long d;        build(1,n,1);        scanf("%d",&q);        while(q--)        {            int flag;            scanf("%d",&flag);            if(flag==1)            {                scanf("%d%d%lld",&x,&y,&z);                update(1,n,1,x,y,z);            }            else            {                scanf("%d%d",&x,&y);                printf("%lld\n",query(1,n,1,x,y));            }        }    }    return 0;}