[洛谷](P3368)【模板】树状数组 2

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题目链接

• 复习树状数组，区间修改，单点查询

#include<bits/stdc++.h>
#define IO          ios_base::sync_with_stdio(0),cin.tie(0),cout.tie(0)
#define pb(x)       push_back(x)
#define sz(x)       (int)(x).size()
#define sc(x)       scanf("%d",&x)
#define pr(x)       printf("%d\n",x)
#define abs(x)      ((x)<0?-(x):x)
#define all(x)      x.begin(),x.end()
using namespace std;
typedef long long ll;
const int mod = 1e9+7;
const double PI = 4*atan(1.0);
const int maxm = 1e8+5;
const int maxn = 5e5+5;
const int INF = 0x3f3f3f3f;
int n,m;
int c[maxn];
inline int read()
{
    char x;
    int u,flag = 0;
    while(x = getchar(),x<'0'||x>'9')
        if(x == '-') flag = 1;
    u = x-'0';
    while(x = getchar(),x>='0' && x<='9') u = (u<<3)+(u<<1)+x-'0';
    if(flag) u = -u;
    return u;
}
inline int lowbit(int x){return x&(-x);}
void update(int st,int x)
{
    for(int i=st;i<=n;i+=lowbit(i)) c[i]+=x;
}
void range_update(int l,int r,int x)
{
    update(l,x),update(r+1,-x);
}
int query(int x)
{
    int res = 0;
    for(int i=x;i;i-=lowbit(i)) res+=c[i];
    return res;
}
int main()
{
    #ifdef LOCAL_FILE
    freopen("in.txt","r",stdin);
    #endif // LOCAL_FILE
    n = read();m = read();
    int l = 0,r;
    for(int i=1;i<=n;i++)
    {
        r = read();
        update(i,r-l);
        l = r;
    }
    while(m--)
    {
        int c,l,r,x;
        c = read();
        if(1&c){
            l = read();r = read();x = read();
            range_update(l,r,x);
        }
        else{
            x = read();
            pr(query(x));
        }
    }
    return 0;
}