codeforces 52 C. Circular RMQ (线段树区间更新,区间询问)

Posted by 111qqz on Sunday, September 25, 2016

TOC

题目链接

题意:一个循环数列,两种操作,一种是把某段区间中加上v,另一种是询问某区间的最小值。对于每个询问,输出答案。

思路:区间更新+区间询问的模板题….

注意体会pushdown以及update的时候。。。

要同时更新tree数组和lazy数组。。。

读入的时候可以用sscanf判断操作类型。。。

/* ***********************************************
Author :111qqz
Created Time :Mon 26 Sep 2016 05:30:21 AM CST
File Name :code/cf/problem/52C.cpp
************************************************ */
#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>
#include <vector>
#include <queue>
#include <set>
#include <map>
#include <string>
#include <cmath>
#include <cstdlib>
#include <ctime>
#define fst first
#define sec second
#define lson l,m,rt<<1
#define rson m+1,r,rt<<1|1
#define ms(a,x) memset(a,x,sizeof(a))
typedef long long LL;
#define pi pair < int ,int >
#define MP make_pair
using namespace std;
const double eps = 1E-8;
const int dx4[4]={1,0,0,-1};
const int dy4[4]={0,-1,1,0};
const int inf = 0x3f3f3f3f;
const int N=2E5+7;
int n,m;
LL a[N];
LL tree[N<<2];
LL lazy[N<<2];
void PushUp( int rt)
{
    tree[rt] = min(tree[rt<<1],tree[rt<<1|1]);
}
void PushDown( int rt)
{
    if (lazy[rt])
    {
    lazy[rt<<1] += lazy[rt];
    lazy[rt<<1|1] +=lazy[rt];
    tree[rt<<1] +=lazy[rt];
    tree[rt<<1|1] +=lazy[rt];
    lazy[rt] =  0;
    }
}
void build(  int l,int r,int rt)
{
    if (rt)
    if (l==r)
    {
    tree[rt] = a[l] ;
    return;
    }
    int m = (l+r)>>1;
    build(lson);
    build(rson);
    PushUp(rt);
}
void update(int L,int R,LL sc,int l,int r,int rt)
{
    if (L<=l&&r<=R)
    {
    lazy[rt] +=sc;
    tree[rt] +=sc;
    return;
    }
    PushDown(rt);
    int m = (l+r)>>1;
    if (L<=m) update(L,R,sc,lson);
    if (R>=m+1) update(L,R,sc,rson);
    PushUp(rt);
}
LL query( int L,int R,int l,int r,int rt)
{
    if (L<=l&&r<=R) return tree[rt];
    PushDown(rt);
    int m = (l+r)>>1;
    LL ret = 1LL<<60;
    if (L<=m) ret = min(ret,query(L,R,lson));
    if (R>=m+1) ret = min(ret,query(L,R,rson));
    return ret;
}
int main()
{
    #ifndef  ONLINE_JUDGE 
    freopen("code/in.txt","r",stdin);
  #endif
    scanf("%d",&n);
    for ( int i = 1 ; i <= n ; i++) scanf("%lld",&a[i]);
    scanf("%d",&m);
    getchar(); //记得回车符。。。
    build(1,n,1);
    while (m--)
    {
        char str[50];
        gets(str);
        int l,r;
        LL v;
        if (sscanf(str,"%d%d%lld",&l,&r,&v)==3)
        {
        l++;
        r++;
        if (l<=r)
        update(l,r,v,1,n,1);
        else update(l,n,v,1,n,1),update(1,r,v,1,n,1);
        }else
        {
        l++;
        r++;
        LL ans;
        if (l<=r)
         ans = query(l,r,1,n,1);
        else ans = min(query(1,r,1,n,1),query(l,n,1,n,1));
        printf("%lld\n",ans);
        }
    }
  #ifndef ONLINE_JUDGE  
  fclose(stdin);
  #endif
    return 0;
}

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