70分，#2,#9,#10WA了
总体思路树状数组+差分
#2提示

Wrong Answer.wrong answer On line 1321 column 1, read 3, expected 1.

#include<cstdio>
#define int long long
class Tree
{
private:
    static const int N=500005;
    int c[N];
    inline int lowbit(int x){return x&(-x);}
public:
    void change(int x,int value,const int &n)
    {
        for(int i=x;i<=n;i+=lowbit(i)) c[i]+=value;
        return;
    }
    int getsum(int x)
    {
        int sum=0;
        for(int i=x;i;i-=lowbit(i)) sum+=c[i];
        return sum;
    }
    int sum(int l,int r){return getsum(r)-getsum(l-1);}
    void diff_change(int l,int r,int value,const int &n)
    {
        change(l,value,n);
        change(r+1,-value,n);
        return;
    }
};
#undef int
int main()
{
#define int long long
    Tree tr;
    int n,m,cur,op,last=0;
    scanf("%lld%lld",&n,&m);
    for(int i=1;i<=n;i++)
    {
        scanf("%lld",&cur);
        tr.change(i,cur-last,n);
        last=cur;
    }
    while(m--)
    {
        scanf("%lld",&op);
        if(op==1)
        {
            int x,y,k;
            scanf("%lld%lld%lld",&x,&y,&k);
            tr.diff_change(x,y,k,n);
        }
        else
        {
            int x;
            scanf("%lld",&x);
            printf("%lld\n",tr.getsum(x));
        }
    }
    return 0;
}