PKU 3468

题目链接：

http://poj.org/problem?id=3468

题解 ：

线段树区间更新模版题。

代码：

#include <string>#include <cstdio>#include <cstring>#include <iostream>#include <algorithm>using namespace std;#define met(a,b) memset(a,b,sizeof(a))#define inf 0x3f3f3f3f#define lchild rt<<1 ,l, m#define rchild rt<<1|1 ,m+1, rtypedef long long ll;const ll maxn = 1e5+10;ll tree[maxn<<2];ll lazy[maxn<<2];void push_up(ll rt){    tree[rt]=tree[rt << 1]+tree[rt<<1|1];}void push_down(ll rt, ll len){    tree[rt << 1] += lazy[rt] * (len - (len >> 1));    lazy[rt << 1] += lazy[rt];    tree[rt << 1 | 1] += lazy[rt] * (len >> 1);    lazy[rt << 1 | 1] += lazy[rt];    lazy[rt] = 0;}void build(ll rt,ll l,ll r){    lazy[rt]=0;    if(l==r)    {        scanf("%lld",&tree[rt]);        return;    }    ll m=(l+r)>>1;    build(lchild);    build(rchild);    push_up(rt);}void update(ll L, ll R, ll delta, ll rt, ll l, ll r ){    if (L <= l && r <= R) {        tree[rt] += delta * (r - l + 1);        lazy[rt] += delta;        return;    }    if (lazy[rt]) push_down(rt, r - l + 1);    ll m = (l + r) >> 1;    if (L <= m) update(L, R, delta, lchild);    if (R > m)  update(L, R, delta, rchild);    push_up(rt);}ll query(ll L, ll R, ll rt, ll l, ll r){    if (L <= l && r <= R) return tree[rt];    if (lazy[rt]) push_down(rt, r - l + 1);    ll m = (l + r) >> 1, ret = 0;    if (L <= m) ret += query(L, R, lchild);    if (R > m)  ret += query(L, R, rchild);    return ret;}int main(){    ll n,q;    while(scanf("%lld%lld",&n,&q)!=EOF)    {        build(1,1,n);        while(q--)        {            char s[10];            scanf("%s",s);            if(s[0]=='C')            {                ll a,b,c;                scanf("%lld%lld%lld",&a,&b,&c);                update(a,b,c,1,1,n);            }            if(s[0]=='Q')            {                ll a,b;                scanf("%lld%lld",&a,&b);                printf("%lld\n",query(a,b,1,1,n));            }        }    }}