#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
typedef queue<int> qi;
typedef set<int> si;
typedef priority_queue<int> pqi;
typedef priority_queue<ll> pql;
typedef priority_queue<int,vi,greater<int> > pqi_g;
typedef priority_queue<ll,vll,greater<ll> > pql_g;
#define F first
#define S second
#define PB push_back
#define PF push_front
#define MP make_pair
#define FOR(i,a,b) for (int i=a; i<=b; i++)
#define _FOR(i,a,b) for (int i=a; i>=b; i--)
#define F0R(i,a,b,x) for (int i=a; i<=b; i+=x)
#define FOR_(x,v) for (auto x : v)
#define F0R_(x,v) for (auto &x : v)
const int INF = 0x3f3f3f3f;
const int maxn = 2e5+2;
const ll MOD = 1e9+7;
//? link: https://oj.uz/problem/view/COCI21_sjeckanje
//? sol: segtree
// - it can be observed that the segments that will produce the max total value are always either increasing or decreasing
// - since the max total value is sum of the difference b/t the max and min values in each segment, we can store the array as one of differences
// - this way, the value for a segment is just the sum of the differences in that segment
// - when making updates, we then only need to change the end values of the segments that are affected
// - we can then use a segtree to store the difference array
// - since each segment must be one spaced apart (can't use the same element twice), we store the max value for each segtree node given 4 scenarios:
// - take the left value and the right value
// - take the left value and not the right value
// - take the right value and not the left value
// - take neither the left value nor the right value
// - we also store the left and right border values for each node
int n, q;
class segtree {
struct node {ll yy,yn,ny,nn,l,r;} d[4*maxn];
private:
ll inline ls(ll x) {return x<<1;}
ll inline rs(ll x) {return x<<1|1;}
node inline op(node &l,node &r) {
node ret = {
max(l.yn+r.yy, l.yy+r.ny), // yy
max(l.yy+r.nn, l.yn+r.yn), // yn
max(l.ny+r.ny, l.nn+r.yy), // ny
max(l.ny+r.nn, l.nn+r.yn), // nn
l.l, // l
r.r // r
};
if ((l.r>=0 && r.l>=0) || (l.r<=0 && r.l<=0)) {
ret.yy = max(ret.yy, l.yy+r.yy);
ret.yn = max(ret.yn, l.yy+r.yn);
ret.ny = max(ret.ny, l.ny+r.yy);
ret.nn = max(ret.nn, l.ny+r.yn);
}
return ret;
}
public:
ll a[maxn];
void init(ll s=1,ll t=n,ll p=1) {
if (s==t) {
d[p] = {abs(a[s]),0,0,0,a[s],a[s]};
return;
}
ll mid = s + ((t-s)>>1);
init(s, mid, ls(p));
init(mid+1, t, rs(p));
d[p] = op(d[ls(p)], d[rs(p)]);
}
void upd(ll v,ll x,ll s=1,ll t=n,ll p=1) { // upd pos v by value x ~ p=cur pos, s,t=cur range
if (s==t) {
a[s] += x;
d[p] = {abs(a[s]),0,0,0,a[s],a[s]};
return;
}
ll mid = s + ((t-s)>>1);
if (v<=mid) upd(v,x,s,mid,ls(p));
else upd(v,x,mid+1,t,rs(p));
d[p] = op(d[ls(p)], d[rs(p)]);
}
ll query() {
return max(d[1].yy, max(d[1].yn, max(d[1].ny, d[1].nn)));
}
void output_a() {
FOR(i,1,n) cout << a[i] << " ";
cout << endl;
}
} st;
int main()
{
// faster cin/cout
ios_base::sync_with_stdio(false);
cin.tie(NULL);
// freopen("c.in","r",stdin);
cin >> n >> q;
int last; cin>>last; st.a[1]=0;
FOR(i,2,n) {
int x; cin>>x;
st.a[i] = x-last;
last = x;
}
st.init();
FOR(_,1,q) {
int l,r,x; cin>>l>>r>>x;
if (l!=1) st.upd(l,x);
if (r!=n) st.upd(r+1,-x);
// st.output_a();
cout << st.query() << endl;
}
return 0;
}
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
1 ms |
348 KB |
Output is correct |
| 2 |
Correct |
1 ms |
348 KB |
Output is correct |
| 3 |
Correct |
1 ms |
348 KB |
Output is correct |
| 4 |
Correct |
1 ms |
348 KB |
Output is correct |
| 5 |
Correct |
1 ms |
348 KB |
Output is correct |
| 6 |
Correct |
1 ms |
348 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
1 ms |
348 KB |
Output is correct |
| 2 |
Correct |
1 ms |
348 KB |
Output is correct |
| 3 |
Correct |
1 ms |
348 KB |
Output is correct |
| 4 |
Correct |
1 ms |
348 KB |
Output is correct |
| 5 |
Correct |
1 ms |
348 KB |
Output is correct |
| 6 |
Correct |
1 ms |
348 KB |
Output is correct |
| 7 |
Correct |
6 ms |
2648 KB |
Output is correct |
| 8 |
Correct |
6 ms |
2652 KB |
Output is correct |
| 9 |
Correct |
7 ms |
2652 KB |
Output is correct |
| 10 |
Correct |
6 ms |
2652 KB |
Output is correct |
| 11 |
Correct |
7 ms |
2624 KB |
Output is correct |
| 12 |
Correct |
6 ms |
2648 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
1 ms |
348 KB |
Output is correct |
| 2 |
Correct |
1 ms |
348 KB |
Output is correct |
| 3 |
Correct |
1 ms |
348 KB |
Output is correct |
| 4 |
Correct |
1 ms |
348 KB |
Output is correct |
| 5 |
Correct |
1 ms |
348 KB |
Output is correct |
| 6 |
Correct |
1 ms |
348 KB |
Output is correct |
| 7 |
Correct |
6 ms |
2648 KB |
Output is correct |
| 8 |
Correct |
6 ms |
2652 KB |
Output is correct |
| 9 |
Correct |
7 ms |
2652 KB |
Output is correct |
| 10 |
Correct |
6 ms |
2652 KB |
Output is correct |
| 11 |
Correct |
7 ms |
2624 KB |
Output is correct |
| 12 |
Correct |
6 ms |
2648 KB |
Output is correct |
| 13 |
Correct |
487 ms |
35888 KB |
Output is correct |
| 14 |
Correct |
467 ms |
35864 KB |
Output is correct |
| 15 |
Correct |
462 ms |
35920 KB |
Output is correct |
| 16 |
Correct |
475 ms |
35700 KB |
Output is correct |
| 17 |
Correct |
463 ms |
35668 KB |
Output is correct |
| 18 |
Correct |
437 ms |
36436 KB |
Output is correct |
